In a large mixing bowl, whisk together flour, baking powder and salt. Set aside.
In a separate bowl, cream butter and sugar with an electric mixer for 1 minute.
Add egg and vanilla then beat until light and fluffy--approximately 5 minutes. Scrape down the sides of the bowl with a spatula as needed.
Reduce mixer speed to low. Add dry ingredients to wet then beat until just combined. Do not overmix batter or cookies will be dry.
Add 1/2 cup of funfetti sprinkles. Using a spoon, stir sprinkles into the dough until evenly distributed.
Use a large 2.5 tablespoon cookie scoop to scoop dough into 12 cookie balls.
Place cookie balls on a large parchment-lined cookie sheet spaced 2 inches apart.
Gently level cookie balls with your fingertips then top each with more funfetti sprinkles.
Cover baking sheet with plastic wrap and chill for a minimum of 2 hours (or up to 3 days).
Preheat oven to 350 degrees.
Bake cookies for 9 - 11 minutes or until edges begin to set but the centers are still soft. Avoid overbaking or cookies will be hard.
Cool cookies on the baking sheet for 5 minutes then transfer cookies to a wire rack to cool completely.
Store cookies in an airtight container at room temperature up to 1 week.