Preheat the oven to 350?F (175?C) and line a muffin tin with cupcake liners.

In a mixing bowl, cream together the softened butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, alternating with the milk, and mix until just combined.

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Bake in the preheated oven for 15-18 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool completely before frosting.

In a mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, mixing well until smooth.

Stir in the vanilla extract and milk until the frosting is light and fluffy.

Frost the cooled cupcakes with the prepared frosting using a spatula or piping bag.

Sprinkle the tops with colorful sprinkles for decoration.