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

Cream together the softened butter and granulated sugar until light and fluffy. Add eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add this to the wet ingredients, alternating with the milk, until just combined.

Divide the batter into four bowls and add food coloring to each, mixing until vibrant.

Layer the colored batters into the cupcake liners, filling each about two-thirds full.

Bake for 18-20 minutes, checking for doneness with a toothpick. Allow to cool in the pan for a few minutes before transferring to a wire rack.

Beat the softened butter for the frosting until creamy, then gradually add powdered sugar and vanilla extract. Add milk until desired consistency is reached.

Frost the cooled cupcakes with the buttercream frosting and add festive decorations.