How to Make a Binary Star Cake

All of this is because I didn't make a death star birthday cake when I said I would. It was Cmdr. Vik's birthday and in repentance, I offered to make him any cake he wanted for his next birthday. He came up with a binary star system cake and then let me think about it for a year.

In this instructable, I'm going to talk about:

1. The materials necessary to do this yourself
2. The steps I took in creating this cake
3. Structural concerns and techniques used.

Step 1: Tools and Materials

Hardware
Wilton Sports Ball Pan Set
2 glass plates
A recycled jar (7")
A 12" vase/carafe
10" round cake base (buy or make from foam core or mdf)
Wooden dowels
6" cake round (make this from foam core or mdf)
Cake release (which can be bought here or made like this)
Pastry brush
metal cake spatula
Weldbond (or any other non-toxic glass glue)
3 travel sized spray bottles


Noms
Cotton candy
Buttercream frosting (a good, crusting, decorator's buttercream. No canned shenanigans)
Pound cake recipe
Vanilla Cake recipe


Decorating
Edible airbrush colour (black, red, blue)
Gold luster dust
Soft Gel paste colour (blue, red)
Vodka
sprinkles (optional)

Step 2: Planning

So there are three real components of this cake; the galaxy, the red giant and the pulsar. I could only find a sphere pan with a 6" diameter, so the rest of the measurements are based around that.

This configuration worked out pretty well and I would use it again.

Step 3: Cake Stand

1. Make sure all your glassware is squeaky clean
2. Using Weldbond, attach your vase/jar to the bottom of the plate. Center the vase/jar the best you can.
3. Let dry. My plates took about 3 days before the glue was totally clear.

What I had wanted to do was turn these into mercury glass pieces but a) I couldn't find looking glass paint in any of my local craft stores and b) I couldn't really find an alternative to the paint that was food safe. C'est la vie!

Step 4: The Base Cake

Baking

1. Heat your oven to 350F (176C) or whatever temperature your recipe wants.
2. Make whatever cake you want to.  Mine was vanilla.
3. Prepare your baking pan by brushing on cake release.
4. Divide the batter equally between the pans and bake for 24 - 30 minutes, or until the cake is done.
5. When done, remove the cake from the oven and let rest for 10 - 15 minutes. The cake is pretty fragile at the point and needs to cool a bit before handling.
6. Remove cake from pan and let cake cool on a wire rack for at least an hour.

Decorating

1. Using a long, serrated knife, cut off the tops of both rounds so that they are level.
2. Place a dab of icing on the 10" cake board and then place your first layer on the round.
3. Put a large portion of icing (about 1 cup) on the top of the first layer and spread evenly to the edges.
4. Add the second layer, cut side down and spread more icing on it.
5. Ice the sides of the cake by applying a heaping tablespoon of frosting to your spatula and then smoothing it onto the cake.
6. Here's a great video on smoothing frosting.
7. Using a spray bottle, apply the black, blue and red edible air brushing liquid in random areas. Use paper towel to dab off any excess colour.
8. Mix .5 oz of vodka with gold luster dust in a spray bottle. Shake to combine and spritz the cake with gold dust to simulate stars.
9. Using a fine paintbrush, create some bigger stars using your gold mixture.

I was actually really happy with this decorating technique. I love the sort of gorgeous, randomness that pictures of galaxy's have and knew that airbrushing would be key.  However, I don't have an airbrushing system and am willing to problem solve. :D

As an alternative to the edible air brushing liquid, you could mix together soft gel colours and vodka (0.5 oz at most) until you have a colour you love.

Step 5: The Pulsar (and Red Dwarf Giant Hemisphere)

Making

1. Make Rice Krispie treats. I added sprinkles to mine.
2. Grease your hands with kitchen spray so that the treats are easier to work with
3. Grease one hemisphere of the Wilton ball pan with cooking spray and fill with warm rice krispie treats.
4. On a sheet of plastic wrap, dump the remaining treat mixture. Close up the plastic wrap around the treats like a bag and shape the treats into a sphere.
5. Cool until room temperature. (About an hour)

You might be asking why I would make one of the sphere's out of rice krispies instead of cake. The answer is weight. The hemispheres of cake are actually quite heavy and I wanted a backup hemisphere in case the cake one wouldn't hold up under the weight of the upper piece. (It didn't, see the last step)

Decorating

1. Lay some plastic wrap between the two cake plates to create a base for your cotton candy wind. It's a good time to now decide on your stand positioning.
2. Using soft gel colours, dye about a 1 cup of frosting blue.
3. Using your metal spatula, coat the rice krispie pulsar in blue icing and then spray with the gold mixture you made for the galaxy.

Step 6: The Red Giant

Baking

1. Heat your oven to 350F (176C) or whatever temperature your recipe wants.
2. Make whatever cake you want to, but I suggest something sturdy like a pound cake.
3. Prepare your baking pan by brushing on cake release.
4. Divide the batter equally between the pans and bake for 30- 50 minutes, or until the cake is done.  
5. When done, remove the cake from the oven and let rest for 10 - 15 minutes. The cake is pretty fragile at the point and needs to cool a bit before handling
6. Remove from pan and let cake cool on a wire rack for at least an hour

Decorating

1. Cut your dowels to the appropriate size (3")
2. Place your bottom hemisphere onto the cake stand and insert the dowels into the cake  near the center. Rest the 6" cake board on top of these dowels and place the other hemisphere of cake on top. Here's a great video on doweling a cake.
3. Mix 4 cups of frosting with red soft gel colour and apply it with a metal spatula. 
4. Spray the red giant with the gold mixture from the galaxy base.
5. Apply your cotton candy right before serving since the moisture from the frosting can make the cotton candy deflate.

Step 7: Noms and Notes

At one point, the cake imploded. The weight of the top layer of cake was too great for the bottom layer and I ended up remaking the sphere using rice krispies. This was after boarding and doweling the cake.  The rice krispies eventually collapsed too, but at that point we decided that this was a natural course of action for a binary star and it was tasty anyways.

Luckily, cotton candy covers all manner of cake sin.


I recommend building thisright before you hope to enjoy it.

If I were to make this again, maybe the red giant would be hollow? I'd love to hear any suggestions from other people who've made spherical cakes. :D