Those impressive, many-layered cakes you see at fancy bakeries aren't as hard to make as you might think. They are basically several small cakes layered on top of one another. For your kid's next birthday party, forgo the bakery route and challenge yourself to make a brightly colored rainbow layer cake. With a little food coloring and several cake pans, your rainbow cake is sure to surprise and delight the kids at the party.
Prepare two batches of vanilla or yellow cake batter. You can make the batter from scratch or use two boxes of cake mix and prepare it according to the directions on the box.
Preheat the oven to the temperature your cake recipe calls for.
Divide the cake batter evenly into six separate bowls and add several drops of food coloring of a different color to each one, using the classic rainbow colors: red, orange, yellow, green, blue and purple. Add more or less food coloring, depending on how intense you want the colors to be.
Line six round cake pans with parchment paper. If you do not have six cake pans, you can bake the cakes in batches.
Fill each cake pan with one of the colored cake batters.
Place the filled cake pans in the oven to bake. You can bake in batches if your oven is not large enough for all the pans. The cakes will be thin, cooking much faster than a regular one-layer cake, so monitor them carefully. They are ready when a toothpick inserted in the center of each comes out clean.
Lift the cakes from the pans with the parchment paper. Put them on wire racks and allow them to cool completely. If you are baking in batches, you can now bake more cake layers.
Slice the tops off of the cakes with a serrated knife to make them uniform and evenly sized.
Lay the first cake on a serving platter and spread frosting on the top with a spatula, leaving about 1/4 inch of space around the edges. Add the second cake on top and frost in the same manner. Repeat with the rest of the cake layers.
Spread a thin layer of frosting onto the cake so it seals in the crumbs. Chill the cake in the refrigerator for about 20 minutes. This will ensure the crumbs are sealed and won't get into the outer frosting.
Generously frost the top and the sides of the cake with the remaining frosting before serving.