Preheat your oven to 350°F (175°C) and line a cupcake pan with colorful liners.

In a stand mixer, cream together 9 tablespoons of softened butter and most of the granulated sugar until light and fluffy.

Melt ¼ cup of white chocolate and let it cool slightly before adding to the butter mixture.

Gradually add 2 cups of all-purpose flour, 1 teaspoon of baking powder, ¼ teaspoon of baking soda, 1 cup plus 1 tablespoon of milk, and 1 teaspoon of vanilla extract to the butter mixture.

Whisk 3 egg whites until fluffy peaks form, gradually adding 1½ tablespoons of reserved sugar.

Fold the whipped egg whites into the batter gently.

Evenly distribute the batter into the cupcake pan, filling each liner about two-thirds full and bake for 19-20 minutes.

Allow the cupcakes to cool completely on a wire rack.

In a clean mixing bowl, cream 2 cups of softened butter until fluffy; gradually add 5½ cups of confectioner's sugar, 1 teaspoon of vanilla extract, and 2 tablespoons of whipping cream.

Divide the buttercream into three bowls; color two with vibrant food coloring.

Use a piece of plastic wrap to layer the colored frosting for a swirl effect and pipe it onto the cooled cupcakes.