A Betty Crocker pound cake mix is used to make this Rainbow Cake that is hollowed out to allow room for lots of candy inside. Decorated with a rainbow of fondant, this cake would be perfect to celebrate just about any occasion.
Here is how to make this colorful, fun, surprise cake...
Preheat oven to 350˚F. Grease two 9" round baking pans with shortening. Dust pans with flour and tap to remove excess.
Beat cake mix and softened butter on low speed until combined. Add water and eggs and beat on low to combine. Mix on medium speed for 2 minutes. Equally divide batter among the two round cake pans (13 ounces in each.) Bake for 22-26 minutes until a toothpick in the center comes out clean. Cool in pans for 10 minutes, then remove and cool completely on a cooling rack.
Measure and cut cakes in half, so you have four rainbow shaped cakes. Set the cakes on top of each other to make sure they are all the same size. If not, cut off any excess.
Set two of the rainbow shaped cake pieces aside. Lay the two remaining cakes flat on a cutting board. Trim off the rounded tops of each cake so that these cakes can be sandwiched flat in between the other two cakes. Then, use a sharp knife to cut a smaller rainbow shape out of the centers of these two cakes, making a well for the candy.
Remove all the scraps and crumbs from your work surface, leaving your two cut-out cakes and two whole cakes.
Pipe Betty Crocker Cake Icing onto one side of a cut-out cake. Place the flat side of one whole cake on top of the icing. Pick up the stacked cakes and turn it upside down, so that the whole cake is now on the bottom and the cut-out cake is on top. Pipe icing along the edge of the cut-out cake, and carefully pick up the other cut-out cake and set it on top.
Pour candy into the cut out area of the cake, filling the hole completely, so that there is no room for the cake to sag once it's upright. Pipe icing around the edge of the top cut-out cake.
Place the flat side of the final cake layer on top. If needed, pipe any remaining icing in between the cake layers to fill in any gaps.
Cut a piece of cake board the size of the bottom of the rainbow cake. Pick up the cake and turn it so that the rainbow is facing you, not laying flat, and set the cake on the board. Use a tub of Betty Crocker Rich and Creamy Vanilla Frosting to frost the cake, making it as smooth as possible.
Color 16 ounces fondant light blue. This will be the sky and it looks good with streaks of darker blue throughout, so there's no need to completely mix the coloring into the fondant.
Lightly grease a cutting board or counter with shortening and roll out fondant into a large rectangle.
Pick up fondant and drape it over cake.
Smooth out fondant.
Cut off any excess fondant from edges of cake. Set cake on a larger cake board. You can use a dab of frosting to hold it in place, if needed.
Create a rainbow by coloring pieces of fondant (about 1 ounce each) using violet, indigo, blue, green, yellow, orange and red coloring. Roll each color into a long log. Set the baking pan used to bake the cake, upside down. Starting with the red fondant, set one log on the pan along the top edge. Set the orange log next to the red. Your fondant pieces may stick to each other if they are a bit sticky. If they don't stick, use a small amount of water as edible glue.
Continue to add rainbow stripes, adding yellow, green, blue, indigo, then finally violet. Cut across the fondant logs in the middle of the cake pan, so your rainbow is the same size as your cake. Remove excess fondant.
Smooth out the rainbow, pressing all the pieces together. Brush one side of the rainbow lightly with water.
Carefully pick up rainbow and press the side that has been brushed with water up against the fondant covered cake. Hold the rainbow in place for about a minute until it adheres to the cake.
To make clouds, pinch off varying sizes of white fondant, roll them into balls. At the end of each side of the rainbow, stack the fondant balls into cloud formations.
Once the clouds are completed your cake is ready to be displayed. I cut my larger cake board to look like a cloud, and set it on a piece of blue sky paper for added affect.
To serve cake, cut and allow candy to fall out. I made a cut in the center of the cake in order to get a nice photo but found that by doing so my candy got covered in crumbs. I suggest you start by cutting off one end of the rainbow cake, allowing the candy to spill out of the cake for more of a piñata like effect.