The ingredients and equipment for this cake can be found at large craft and hobby stores, cake specialty stores and even on Ebay.
Ingredients and Equipment
3 boxes of white cake mix (or make your own using your favorite recipe)
Shop bought white Buttercream or Frosting (or make your own using your favorite recipe)
Rolled Fondant or Pettince 44 oz or 1300 grams *
Pink, violet, blue, green and yellow gel food color (I used Wilton)
Large rolling pin
cornflour (corn starch)
Small Rolling Pin
Large knife for trimming the cake
Small sharp knife
Cake smoothers X 2
Frilling tool - if you do not have a frilling tool a toothpick can be used for a similar result
Not stick flower molding mat
Small brush and water
*Fondant dries out really quickly - keep it in an airtight container or ziplock bag in between use and work really quickly.
The night before decorating the cake color the fondant with the gel colors as follows: 8 oz (240 g)pink, 4 oz (120 g) violet, 4 oz l(120 g) light blue, 4 oz (120 g)light green and 4 oz (120 g) light yellow, the remaining 20 oz (580 grams)should remain plain white.
To color fondant knead until soft and then add the gel food color a drop at a time kneading well until the desired color is achieved. Store in an airtight container until ready to use.
You will need to bake 5 seperate cakes for the different layers, but if you only have 1 or 2 X 8" baking tins that is ok, just grease and flour the tins you have and once you have baked a cake and the tin has cooled down you can wipe it out and reuse for the next color.
Make up the cake batter and divide the mixture evenly between 5 bowls. Add 1/4 tsp of the pink gel food color to first bowl and mix until combined and there are no streaks, if you need add more color until you have achieved a pretty pastel color. Any of the mix you are not baking straight away (because you don't have enough pans or room in your oven) pop into the fridge* .
Repeat this process for the four remaining bowls of cake batter, adding violet to one, light green to another, yellow to another and light blue to the final batch.
Pour each separate mixture into a separate baking tin and then bake in an oven following the directions on the packet mix box, check 10 minutes prior to the recommended baking time by inserting a toothpick or skewer into the cake to see it is cooked through. If it is not cooked through continue to bake for 5 - 10 minutes until no crumbs stick to the toothpick or skewer.
Once the cakes are cookid remove from oven. Leave in pan for 5 minutes and then turn out onto a wire rack to cool.
*popping the unbaked cake batter mixture in the fridge will slow down any type of 'baking' reaction due to mixing the ingredients together
Step 2: Stack the Cakes and Cover in Buttercream
Take the cake board and starting with the yellow cake layer for the base pop a little of the butter cream in the center to secure the cake. Then add a layer of the white frosting or butter cream and then add the green cake layer and pop the cake into the fridge for 10 to 15 minutes to chill.
Start to stack each of the rainbow layers of cake adding a layer of frosting or butter cream in between each layer.
Once the final pink cake layer is in place and chilled spread a thin layer of butter cream around the edges and made the cake as smooth as possible. Well as smooth as possible without going overboard remember there will be lots of ruffles covering this cake. Chill the cake again until the butter cream is firm.
At this stage take a piece of paper and mark on it where each different layer of cake ends/starts to use as a guide for the ruffles.
Step 3: Cover the Cake With Fondant
Measure around the cake with a piece of string to work out how long your fondant will need to be and then measure the height.
You will need to roll out a piece of fondant that you can cut into a rectangle the size that you have measured.
Roll out the white fondant on a workbench dusted with a little cornflour (corn starch). Turn and lift the fondant often to make sure it does not stick and try and roll out in a rectangular (ish) shape.
Once the fondant is big enough trim along the top to get a straight line. Take the cake out of the fridge and lay it sideways onto the fondant so that you can wrap the fondant around the cake. Where the fondant joins at the back you can wrap one layer over the other and then using a sharp knife cut down in a straight line. Lift up the fondant and remove any excess underneath and smooth the cut line together with your finger. Don't get too uptight about making the finish really smooth, it's all going to be covered with ruffles.
Pop the cake upright and use the sharp knife to trim off the fondant from around the bottom of the cake, and use fondant smoothers to make sure that the cake is smooth.
Take the pink fondant and roll it out on a cornflour (corn starch) dusted work bench until very thin and using the cake tin that you used to bake the cakes in press down to cut out a round the approximate size of the cake. Place it on top of the cake and use the fondant smoothers to make the top as smooth as you can.
Take the piece of paper where you marked where the cake layers started and ended and using a knife make a little indent so you will know where each color ends/starts to use as a guide for your ruffles.
Step 4: How to Make the Ruffles
Starting with the pink fondant, dust the workbench with cornflour (cornstarch), take a piece of fondant about 1 1/2 tsp and shape it into a rectangle, using the small rolling pink roll in out into a long strip. As you roll you may need to press the sides in carefully with the sides/heels of you hands to stop it from getting too wide. (or if you find that is not working you can always use a sharp knife to trim it back to size) Keep rolling until the strip is quite thin. I like to pick the strip up after each roll to ensure it is not sticking to the bench and when necessary dust underneath again.
When you have rolled out as thing as you can on the workbench, pick up the strip of fondant and place onto a nonstick foam (the type you use for making fondant flowers) and using the middle section of the frilling tool roll back and forth (like using a rolling pin) to make the strip even thinner, you will probably get it to double in length.
Then use the pointed edge of the frilling tool rolling back and forth along one edge of the strip a little more to make it a little ruffly.
Step 5: Appling the Ruffles to the Cake
Continue making pink strips of fondant and attaching them to the cake working your way down the cake until you reach the indent that indicated you should start with the next color and follow the instructions this time making violet ruffles. Follow this process for all the remaining colors until the cake is completely covered with ruffles.
As you work your way down, some of the ruffles may fall down and look floppy, you can brush a tiny amount of water around the middle section of the fallen ruffle and press it up so it is upright, but this look is not about perfection so some floppy areas will work just fine.
At the very bottom of the cake roll out a strip of yellow around 1/3 the width of the regular strips and without ruffling it adhered it around the bottom to cover any of the uneven ruffle bottoms and make a clean finish.
Cake can be made the day before serving, store at room temperature. Do not store in a fridge or put in an airtight container (Butter creams that require refrigeration will not be suitable for this cake).
Now you can slice into it and enjoy.