Preheat oven to 350°F (175°C) and grease two round cake pans.

In a bowl, whisk together flour and baking powder.

Cream the butter and sugar until light and fluffy; add eggs one at a time, then stir in vanilla.

Gradually alternate adding the dry ingredients and milk to the mixture until smooth.

Divide batter into two bowls; tint one with pink food coloring.

Alternate spoonfuls of each batter into the pans; swirl gently with a knife.

Bake for 25–30 minutes or until a toothpick comes out clean. Cool before frosting.