Preheat Oven & Prepare Cupcake Tin:
Preheat the oven to 350°F (175°C) and line a 12-count muffin tin with cupcake liners.

Make the Cupcake Batter:
In a stand mixer, combine butter, sugar, eggs, and vanilla extract. Mix until smooth. Gradually add in flour, baking powder, and milk, mixing until fully incorporated.

Divide and Color the Batter:
Separate the batter into three bowls. Add red food coloring to one bowl, blue food coloring to another, and leave the third bowl plain.

Fill the Cupcake Liners:
Scoop 1 1/2 tablespoons of each colored batter into the cupcake liners, layering red, white, and blue.

Bake:
Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean. Allow to cool completely.

Make the Frosting:
In a stand mixer, combine butter, powdered sugar, vanilla extract, and milk to create a smooth frosting. Divide the frosting into three bowls and color one red, one blue, and leave the third white.

Frost the Cupcakes:
Use a piping bag with a star tip or the plastic wrap method to swirl the frosting onto each cupcake.

Serve and Enjoy!
Let the cupcakes sit for a few minutes to set the frosting before serving.