Vanilla Buttermilk Cupcakes

1-1/2 cups flour
1-1/4 tsp baking powder
1/4 tsp baking soda
1/4 tsp salt
1-1/2 sticks unsalted butter, softened
1 cup sugar
2 large eggs
1 egg yolk
1-1/2 tsp vanilla extract
1/2 cup buttermilk

Preheat oven to 350. Fill a 12 cup muffin tin with cupcake liners. Whisk together the flour, baking powder, baking soda, and salt.

Beat butter and sugar until fluffy. One by one, mix in eggs, the egg yolk, and vanilla. Add the flour mixture alternately with the buttermilk, mixing until smooth. Spoon out the batter.

Bake for about 25 minutes. Cool, top with your favorite frosting.