Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.
Mix dry ingredients: In a bowl, whisk together flour, baking powder, and salt.
Cream butter and sugar: In a separate bowl, beat butter and sugar until light and fluffy.
Add eggs and vanilla: Mix in eggs one at a time, then add vanilla.
Combine and add milk: Gradually add the dry ingredients to the wet mixture, alternating with milk.
Fill liners: Divide the batter evenly into the cupcake liners, filling each about 2/3 full.
Bake: Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean. Cool completely.
Prepare frosting: Beat butter until smooth, add powdered sugar gradually, then mix in vanilla and milk until desired consistency.
Color the frosting: Divide the frosting into bowls and tint each with gel food coloring.
Decorate: Use piping bags to pipe character-themed designs and add Paw Patrol toppers.