Preheat your oven to 350°F (175°C) and line a cupcake tray with liners.
In a bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract.
In another bowl, combine flour and baking powder.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Divide the batter into five bowls and color each with a different food coloring.
Layer the colored batter in the cupcake liners, starting with purple, followed by blue, green, yellow, and red.
Bake for 15-20 minutes or until a toothpick comes out clean.
Let cool completely before frosting.