For Halloween, decorate the tops of the cupcakes with black and orange jelly beans.
Preheat oven to 350 degrees. Line a standard (12-cup) muffin tin with paper liners. In a small bowl, whisk together flour, baking powder, and salt; set aside.
With an electric mixer, beat butter and sugar until light and fluffy, about 5 minutes. Beat in eggs, one at a time, until combined. Beat in vanilla.
With the mixer on low speed, gradually beat in flour mixture and sour cream in alternating batches, beginning and ending with the flour. Divide batter evenly among prepared muffin cups.
Bake until a toothpick inserted in the center of a cupcake comes out clean and the top is springy to the touch, 20 to 25 minutes. Cool 10 minutes in the pan, then turn out onto a rack to cool completely before spreading with frosting.
Reduced-fat sour cream works as well as the regular version in giving these cupcakes a moist crumb and slightly tangy taste.