My first successful rainbow cake! And it's so beautiful! :'D I'll put up the recipe if anyone wants. C:

After the request of a few people, here's the recipe!
Ingredients:
2 1/2 cups of sifted cake flour
1 1/2 teaspoons baking powder
1/2 teaspoon baking soda
3/4 cup unsalted butter at room temp. and extra for greasing
1 1/2 cups granulated sugar
3 large eggs
2 teaspoons vanilla extract
1 cup buttermilk
Food Coloring (red, orange, yellow, green, blue, and purple)

Preheat oven to 350^oF (180^oC). Lightly grease the bottoms of two 8 or 9 inch round cake pans. (I used a springform pan). In a bowl, whisk together the flour, baking powder, baking soda, amd salt until well blended. In another bowl, using a mixer on medium speed, beat the butter until smooth. Slowly add the granulated sugar and continue beating until well blended and fluffy. Add the eggs one at a time, beating well after each one, until just blended. Beat in vanilla. Add flour mixture and the buttermilk.

After everything's well blended, divide the batter into six different bowls. Add red, orange, yellow, green, blue, and purple food coloring into different bowls. Let all bowls of batter chill for 15 minutes in the fridge. After chilling, pour a bowl of batter one at a time into the cake pan(s). Make sure you keep your pour centered. Then place the cake pan(s) into the middle rack of the oven. Bake until toothpick inserted into the center of the cake(s) comes out clean. Baking time is a around 25-35 minutes. Let the cake(s) cool on a rack for 15 minutes. Make sure the cake completely cool before frosting.

Frost, decorate, and enjoy!