Introduction: Two-Faced LED Pumpkin Cake

About: Hi there! My name is Katarina, and me and my partner have been running our small computer repair business since 2008. In addition to my expertise in IT, I am also passionate about DIY and crafts. I am always e…

For this year's Halloween I've decided to make something different. I really enjoy pumpkin carving, but don't really like throwing it all away after a few days (I like eating it, pumpkin soup mmmmmm :D).

So I thought maybe a pumpkin cake would be an interesting idea, but I still wanted it to light up and that's how I came up with the LED Pumpkin Cake with Multiple Personalities.

In my experience a cake like this will happily last for around 10 days maybe a bit longer and it definitely doesn't need to go in the fridge, in fact doing so will spoil it. I made it a week before Halloween and used it as a decoration throughout the holiday.

I made a few mistakes in the process (mainly because I didn't really have a plan, I like to make things up on the go), but all in all I'm really pleased with the result.

If you like you can watch the whole process here ;)

You could also use this technique to make a ball shaped cake without having to bake multiple cakes.

I never had any culinary or cake decorating training and I most definitely wouldn't consider myself a professional, even though I've made quite a few cakes in the past. All I can show you is what I've learned myself mainly by making mistakes, so please forgive me if I don't name the things correctly.

Step 1: It's All About That Base


  • 12" cake drum
  • RGB LED bulb + remote, I bought this one
  • old lamp or something like this
  • glass bowl vase
  • smallish cardboard box


  • small flat head screwdriver
  • pencil
  • hobby knife
  • ruler
  • drill with holesaw bit
  • hot glue gun
  • aluminium foil tape (if you don't already have this, you should definitely buy it, it's awesome, it sticks really well and you can use it for various things, e.g. if you can't replace the silicone round the bath, use this, it will last over a year before needing to be replaced (I've lived in a rented property before where I couldn't perform any permanent DIY :D))

Disassemble the old lamp and pop the diffuser off of the LED bulb with a small flat headed screwdriver (you might want to wear gloves or at least be very careful, the heat sink on mine has very sharp edges). Screw the bulb in the lamp. Draw and cut out a hole in the top of the cardboard box. Cut one of the sides of the box and and put the lamp in the box so that the cable goes out of the corner.

Find the middle of the cake drum and with a holesaw bit, drill a hole out (you want the hole to be slightly larger than the bulb). If you don't have a drill you could just cut the hole out with a knife or whatever else you feel comfortable using. Cover the opening with the aluminium tape.

Hot glue the vase to the cake drum and clean it with a cloth.

Step 2: Bake a Cake

For the cake you're going to need:

  • 360g butter
  • 360g caster sugar
  • 290g self-raising flour (sieved)
  • 70g cocoa powder
  • 6 eggs

You will also need baking paper, 10" baking tin, scales and a mixer.

Start by mixing the butter with sugar, once mixed, add eggs one by one and for every egg add two tablespoons of flour and cocoa powder mixed together. Then slowly add the rest of the flour-cocoa mixture. Line the baking tin with baking paper (you can use a bit of butter to stick it to the sides) and add the batter. Bake in the oven for 65-75 minutes at 160°C/320°F. Cool on wire rack.

Step 3: Buttercream

Buttercream icing:

  • 450g butter
  • 1350g icing sugar (sieved)
  • 12 tbsp milk
  • 6 tsp orange extract
  • yellow and red food colouring (or orange)

Sieve the icing sugar into mixer bowl and add butter, milk and orange extract. Start mixing at a lower speed and if your mixer doesn't have a lid, cover it with a cloth, otherwise it could get really messy. Mix on high speed until nice and creamy.

Keep adding little bits of the food colouring until you get a nice orange shade. Leave the buttercream in the mixer bowl and cover it with cling film so that it doesn't dry and get crusty.

Step 4: Cut the Cake

I've "calculated" that I would need approximately 125 cubes. I measured the circumference of the vase at every 3cm from the bottom of the vase upwards (50cm, 58cm, 62cm, 60cm, 52cm, 42cm, 28cm), added that together and divided that by the cube size (originally I wanted 3cm x 3cm x 3cm sized cubes).

Once I had baked the cake, it was less than 3cm high around the edges and more than 3cm high in the middle, so I was worried that I might not have enough cake. So I decided to cut the cake halfway and then I made a mark and cut at every 2.1 cm vertically and horizontally.

I ended up with 288 cake cubes sized 2.1cm x 2.1cm x 1.5cm approximately (some of them were quite a bit taller but it still worked out).

Step 5: "Bricklaying"

For this step you will need a turn table and a small palette knife (cutlery knife or spoon).

Put a bit of the buttercream into a smaller bowl, leaving the rest of it still covered (if the buttercream gets crusty it won't stick to the cake properly). Start adding the cake cubes onto the cake board as if you were laying bricks (I do apologise to all professional bricklayers out there, this probably isn't how it should be done :D)

With a small palette knife spread the buttercream onto the cake board and the vase and add your first cake cube. Do the same for the rest of them but add a bit of buttercream to the side of each cake cube. Gently press each of the cubes as you are adding them to your structure.

For the second and all other rows proceeding, continue laying the cubes on, ensuring that the vertical joint of the cubes on the upper row align to the middle of the cubes of that below. It might not work out all the way, in which case you can cut the next cube in half. This will ensure the stability of the structure as you build it.

Once you have the vase covered with cake cubes, press it firmly with your hands against the vase all the way around. Let your "Death Star" rest in the fridge for half an hour.

The cake should now be nice and firm, so if needed you can now shave it into a more desired shape with a bread knife.

Step 6: Carve Your "Pumpkin"

For this step I must admit I was a bit premature. My original plan, if I ever had one, was to carve it once the roll out icing was in place and dry. But I did get exited and went for it. Needless to say the structure started to collapse a little, however every cloud has a silver lining and this mistake has added a badass jawline to the scary side of the pumpkin face :D

So if you wish to recreate my error here is what I did:

I cut out the templates (included in the introduction) and pinned them to the cake (only placing pins around a piece of cake that I would later be removing). Then I carved them with a hobby knife and carefully pulled out the insides with a leaf shaping tool. I did the same for the front. Then I spread the rest of the butter cream onto the cake using the palette knife and a smaller palette knife for the openings.

If at this point you need to leave the cake and can't carry on covering it with the icing, wrap it in a cling film. Don't put it in the fridge any further. If you leave the cake in the fridge for longer than half an hour, you could have a problem with air bubbles once the cake is covered in icing. I learned this the hard way so you don't have to. (Still don't really know why this happens, never bothered to find out, maybe as the air gets warmer it expands? if you do know please comment) Here is an example of what I mean. (I had proceeded to cover the example cake with icing, got the sides and edges the way I wanted them and an hour later a big bulge had appeared on the side. I'm not sure if anything can be done about it to successfully repair the damage once it has been caused. I tried pricking and squeezing it but it was still quite visible. Now I always put the rear side of the cake closest to the back of the fridge, because that's where this issue would usually occur. It also could be due to my fridge, so it might not happen to you, but I wouldn't risk it ;)

Step 7: Support

This step probably wouldn't be necessary if I didn't carve my "pumpkin" prematurely. If I was making it again I would make this a second step and I would then have hot glued it to the vase.

For this step you will need:

  • couple of empty and washed aluminium cans (in this case beer cans my bf had no longer any use for)
  • printed template
  • scissors
  • pencil
  • sharpie
  • ruler
  • clear tape

Start by cutting off the top and bottom of the can and slicing it open (you can use scissors or a knife for this). Wash it thoroughly. Cut the can into 2 cm strips and tape them together. With the help of the template bend the strips into the desired shapes (mouth, eyes and nose) You can mark where the bends of the aluminium strips should be with a marker. Use the clear tape to join the strips wherever needed. Clean your newly constructed "cookie cutters" again and press them into the cake where you wish your cut outs to be. Pull the insides out with the leaf shaping tool or knife.

Step 8: Roll That Icing

For this step you will need:

  • 1.5 kg ready to roll icing
  • rolling pin
  • icing sugar
  • food colouring (yellow, red)
  • cake smoother
  • modelling tools (leaf shaping and blade tool)
  • knife and ruler

If your ready to roll icing is too hard, you can leave it, still closed in its packaging, on the radiator for 20 minutes. After that it should be really easy to work with. Start by mixing approximately 1 kg of the icing with yellow and red food colouring.

Once you achieve the desired shade of orange, sprinkle some icing sugar onto the work top and roll out the icing. You want it to be roughly 4 mm thick. To make sure it's large enough to cover the cake, measure the height twice and width once. It doesn't have to be exact, you can do this either with a tape measure or the rolling pin itself. Once you're happy with the scale of the icing, fold it over the rolling pin and transfer it onto the cake.

Once you have the icing on the cake, you need to work quite quickly, otherwise cracks might start appearing in the icing. Start from the top smoothing the icing with your hand in a downwards direction. The top half should be quite easy. When you get passed that, continue with your left hand smoothing the icing around the cake in small sections whilst gently pulling the icing outwards with your right hand as you go along. If you get any folds in the icing, don't worry just gently lift the icing outwards again and smooth with hand as you go. (If all else fails and you still have lots of cracks and/or folds you can still fix this. Smooth it out as much as possible, cut off any protruding folds ensuring the cake is covered in icing everywhere. Roll out more icing and cover it again. It should be much easier this time around).

Cut off the leftover icing around the cake base with a knife and run your cake smoother over it again. Prick a small hole in the icing for all of the openings in the cake (eyes, nose, mouth and teeth). Mark the points on the cake drum, where you would like the pumpkin lines to be (it's easier to have a reference than working it out as you go along). Align the ruler with the marker point on the drum and top of the pumpkin head and press the ruler into the cake, making a line from bottom to the top. Do this for every marker point, or wherever you see fit for the desired effect.

Trace the lines with the leaf shaping tool for a nicer finish and then cut out the eyes, nose, mouth and teeth.

At this stage as you can see from my photos I had quite a few cracks in the icing, but I wasn't really bothered. It's meant to be a pumpkin and doesn't need to be perfect, but I'll show you later how to fix some of them. I do tend to use the supermarket ready to roll icing, because its cheaper, but I've used the more expensive icing in past and that didn't seem to develop as many cracks, so I suppose it's all up to you how much you're willing to spend.

Also you should be able to see on the photos, that at this point the centre of the face on the scary side was still collapsing slightly, so I added a little bottle top in the mouth for extra support.

Step 9: Put a Smile on His Face

Some of the things you might need:

  • small rolling pin
  • food colouring (yellow, red, blue, black)
  • vodka
  • modelling tools (leaf shaping and blade tool)
  • set of brushes

Make green icing by adding a little bit of yellow and blue to the icing. Roll out a cone and with the leaf shaping tool, make indentations all around and then gently twist it. Put small amount of vodka into a bowl or a cup. With a brush dipped into the vodka, paint the top of the pumpkin and place the stem onto his head. Whilst holding it, gently press the sides of the stem into the head with the leaf shaping tool. Fold a piece of kitchen towel and place it under the end of stem for support while it dries.

Cut out the template, pin it to the cake and trace around so that you have a guide later. At this point I decided to make the eyes slightly larger on the happy side of pumpkin.

Roll out some white icing and cut out the whites of the eyes using the template. Spread vodka onto the cake where the eyes will go and attach them on. Gently shape the icing with your finger. Do the same for his mouth, blue and black parts of the eyes.

Roll out strings from the black icing for the lining around the eyes, mouth and nose. Start with your hands and carry on with the cake smoother. I think this is one of those points where a video demonstrates this much better :)

Step 10: Make Him Scary

First of all I needed to clean the inside of his eyes. It's easier to do this when the buttercream has dried a bit. I scraped off as much as I could and then cleaned it with the cotton buds dunked into the vodka.

Roll out the black icing and cut it into strips approximately 2.5cm wide. Paint the vodka onto the inside of the eyes and about 4mm around the outside of the eyes. Place the strip into the eye and smooth it out with the leaf shaping tool. Use the blade tool for the corners. Do the same for nose and mouth.

Step 11: Accessorize

Cut out the leaf template and roll out green icing. Trace around with a knife and leaf shaping tool.

Affix the leaf in place with a bit of vodka, lift it up in few places to make it look more alive and put some scrunched up kitchen towel under to support it until it dries.

Make a few green strings out of the icing, using the same technique as for the eyes, but this time make them slightly thicker. Cut a little piece for the leaf stem and again put some kitchen towel under. Chop a few longer ones for the "hair" and stick them on with the vodka.

Add a little bit of the red food colouring to the orange icing, to give it a different shade of orange and cut 5 identical pieces. Shape them into a tear drop and flatten them out. Trace the edges with the leaf shaping tool, glue them together with the vodka into a circle and with the leaf tool keep pulling the thicker ends towards the middle, until they join each other. Affix it onto the pumpkin with vodka and fill the centre with more icing. Add a little ball to the middle.

Step 12: Fix the Cracks

Don't do this unless the icing is quite firm to the touch, if you try to fix the cracks right after covering your cake, you will most likely end up with an indent which wouldn't look very nice.

Apply a little bit of vodka onto the crack you wish to fix. Take a small ball of icing and knead it until very flexible. Place it onto the crack and smooth it in with the leaf tool.

Step 13: Makeup Time

Mix a little bit of the black food colouring with vodka and paint the "wrinkle" lines on the face with a small paint brush. Do the same for the leaf but with green colour and red for the flower. For shading use a larger paint brush.

To finish off, mix the white luster dust with a tiny amount of vodka and make a dot in each eye of the smiley face. Dunk a larger, dry paint brush in the red luster dust and apply it to the cheeks in circular motions.

Step 14: Lumos Maxima

Place the cake onto two platforms similar in height with a gap in between. Put the LED light inside, turn it on and find a position that works best for projection onto the wall. Glue it in place with hot glue and carefully put the cake onto the cardboard box, allowing the bottom end of the lamp to fit through the hole previously made.

Glue the cake drum and the box together with the hot glue.

Step 15: Back to the Base

For this step you will need some stringy LED type lights, scarf and some creepy crawlies for later (I got all of the mentioned at poundland).

Start by gluing the ends of the scarf together and onto the cake drum as close to the cake as you can. Turn the cake around, so the smiley side is facing you, pull the scarf towards you and find the middle. Glue it to the cake drum. Carry on around the cake, always finding the middle of a section and then gluing it to the drum until the scarf is all in place. If your scarf is quite a wide one, you can glue the other side on too, just like I did or you could fold the scarf lengthways before you start gluing. (I glued the scarf on the wrong way around, by the time I noticed it was too late to do anything about it, but I think I prefer it double layered).

Measure the circumference of the drum and divide the number by the number of LEDs on the string. Remove the LED covers. Make a mark for each LED on the cake drum and glue them in place one by one. Glue the battery holder and LED cables on the drum as well. Make a hole in the scarf/skirt with small scissors and poke each LED through. You can now place the LED covers back on.

For the bottom part, cut out two 12" circles of cardboard, glue them together and repeat the LED gluing process.

Step 16: Finished Pumpkin

For an interesting effect on the wall, cut out the two small pumpkins (included in the pdf template) and colour them black with a marker. Place one in each eye and turn the LED light on.

Step 17: Pumpkins Little Chums

For this step you will need some sweeties, mandarins, bananas and cake pop bags.

Put a selection of sweeties in the cake pop bags and tie them up.

With a marker draw cute faces on the mandarins, bananas and whatever else you find around the house. Onions work quite well ;)

Step 18: Final Result

To set up the table, lay out a black tablecloth (or a window blind in my case) and spread the spider web around. "Strategically" place the bananas, mandarins, sweeties, creepy crawlies and whatever else you fancy around for effect.

Step 19: Turn the Lights Off

You could leave your cake on the turn table so that you can easily enjoy your creation from all sides. In the daytime you can enjoy having your pumpkin smiling at you. In the evening when its time to turn out the lights you can enjoy the scary face projecting onto the wall or whichever way round you fancy, have a play with it, and have fun.

Also it might be interesting to try setting it up near the window, so that it projects onto the blinds (I regret not trying that one myself :()

Step 20: Photo Time

Don't forget to take plenty of photos with your pumpkin, because once you've cut it and eaten it, the memories will be the only thing left to look back upon.

Also the Instructables editor has a really cool photo editing facility, you might want to give it a go ;)

Step 21: Conclusion

I really like my little pumpkin friend and it almost felt wrong to cut into servings after. Saying that, the chocolate cake with the orange flavoured buttercream made it all worthwhile :D

In the process I made quite a few mistakes, which I tried to point out as well as I could during this write up, as I really wanted to show you that if an error occurs it can usually be fixed or well hidden. I work as an IT technician during the day. Everything I have learnt in my time has purely been through trial and error (including cake making, woodworking, sewing, knitting, crochet, a bit of plumbing, the IT bit of course and plenty more). Don't let anything stop you from learning and pursuing your interests :)

I spent about £16 on this project (I only had to buy the bulb, vase and a few Halloween bits and bobs) and it took me approximately 20 hours over three days to complete. Fantastic fun it was!

I hope you also enjoyed my Halloween Instructable as I did.

Thank you for taking the time to visit my project, I wish you the best of luck and a lovely day ;)

Pumpkin Carving Contest 2016

Runner Up in the
Pumpkin Carving Contest 2016

Halloween Food Contest 2016

Runner Up in the
Halloween Food Contest 2016

Halloween Decor Contest 2016

Participated in the
Halloween Decor Contest 2016