Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, beat the softened butter and sugar until light and fluffy.

Add eggs one at a time, beating well after each addition. Stir in the vanilla extract.

Mix in the sour cream until smooth and fully combined.

Add the dry ingredients in three parts, alternating with the buttermilk. Begin and end with the dry mixture. Stir gently after each addition.

Gently fold in the sprinkles using a spatula.

Divide batter evenly into the cupcake liners, filling each about ⅔ full.

Bake for 18–21 minutes or until a toothpick inserted in the center comes out clean.

Let cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Frost with vanilla buttercream and decorate with extra sprinkles if desired.