Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans.

In a bowl, whisk together flour, baking powder, and salt.

In a separate large bowl, cream the softened butter and sugar until light and fluffy.

Add eggs one at a time, mixing well after each addition.

Stir in vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with milk, until fully combined.

Divide the batter into two bowls. Add blue food coloring to one and pink to the other, mixing until desired shades are achieved.

Pour the blue batter into one prepared pan and the pink into the other.

Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer to racks to cool completely.

Once cooled, frost the cakes with buttercream frosting and decorate with cotton candy.