This instruction is to create 9" diameter checkerboard rainbow cake. It is a six-layered cake with six colors (red/pink, orange, yellow, green, blue, and purple). Each cake layer contains a three color combination. You need to have three dividers to arrange the colors. I created the cake divider with my 3D printer, and the stl object is available to download here: CAKE DIVIDER
After printing the Cake Divider, please sand the surface until really smooth with either sandpaper or by applying smooth-on XTC-3D. The smoother the surface, the less cake batter attached to it. Please be sure to clean and rinse the Cake Divider thoroughly after the smoothing process is done. It is very important not to leave any PLA or ABS residue before using it to make the cake.
This Cake Divider helps me to create color combinations for each cake layer easily, and the colorful cake layers will bond strongly after baking, with no cracking or separating at all. I don't need to use any frosting at all to attach each colored cake section to another. I prefer to use less frosting because the cake will not be too overwhelmingly sweet and to reduce excessive calories as well.
Ingredients to make the cake:
2 boxes vanilla cake mix (each box is about 15.25 oz) → can be any brand, I choose Betty Crocker Cake Mix
2 cups water
1 cup vegetable oil
cake/food colors (red, orange, yellow, green, blue, purple)
cake frosting (about 32 oz.) → can be any brand, I choose Betty Crocker Dark Chocolate Frosting
six 9" baking cake pans
3 cake dividers (print it with 3D printer)
Step 1: Mix the Cake
1. Prepare six 9" baking cake pan with the three dividers.
2. Apply butter or margarine generously to the surface of the pans.
3. In a large bowl, mix the cake flour, vegetable oil, eggs, and water. Use mixer with low speed about two to three minutes.
4. Divide the batter evenly among six small cups.
Step 6: Color the Batter
1. Put several drops of red/pink (I choose pink because I like it better than red) color in the first cup, then several drops of orange color to the second cup, then yellow color drops to the third cup, green drops to the fourth cup, blue drops to the fifth cup, and purple to the sixth cup. Mix the color in each cup thoroughly. I used plastic knife to mix it well.
2. Place the three Cake Dividers on the three pans and divide the pink, orange, and yellow batter among the three pans. I find out that the easiest way to divide the batter is by placing each color little by little to all right positions in the pans first, and keep adding them equally until finish. For example, put two spoons of the pink colored batter to the outer circle of the first pan, then put two spoons to the middle circle of the second pan, then put two spoon to the center circle of the third pan. Repeat this process until all pink batter is divided equally among three pans.
3. Repeat the same process with the orange and yellow batter.
4. Remove the dividers very carefully from the pan, and wash them cleanly, and put them on the rest of three pans.
5. Divide green, blue and purple batter among the other three pans.
6. Remove the dividers carefully from the pans, and wash them clean.
7. Heat the oven to 350°F. (You can do this step earlier if preferred)
8. Bake 18 to 20 minutes or until cake springs back when touched lightly in center and begins to pull away from side of pan. Cool 10 minutes. Remove from pans to cooling racks; cool completely.
Step 12: Stack 'Em Up
1. Level each cake by removing any dome from the top. It is important that the layers have the same height so you can stack them up easily. You can remove the dome by either using a long kitchen knife or a cake cutter.
2. Set one of the six cake layers on the serving plate. I preferred the layer with outer purple color to be the base of my cake.
3. Spread the whip filling on top of the bottom layer, leaving about 1/8-1/4 inch from the edge.
4. Place next layer of cake on top, which, in my case is the layer with purple circle in the middle.
5. The next layer for me is the one with purple circle in the middle. Then, the layer with outer pink color, then layer with pink color in the middle, then layer with pink color in the center. Repeat filling remaining layers.
6. Get all of the sides covered, you’ll want to work to smooth the top and the sides.
7. Cut the cake and share it with others. They will be asking "How did you make this cake?" A LOT.