Classic Vanilla Cupcakes

Adjust oven rack to middle position and preheat oven to 350°F (175ºC). Place paper baking cups in two 12-cup muffin pans. Fit a piping bag with desired piping tip; set aside.

In a medium bowl, whisk flour, baking powder, and salt to combine; set aside. In a small bowl, whisk together whole milk and sour cream until smooth; set aside.

In a stand mixer fitted with a paddle attachment, beat butter and sugar together on medium speed until light and fluffy, about 4 minutes. Add eggs, 1 at a time, beating well after each addition, followed by the vanilla. Reduce speed to low and add about 1/4 of the flour mixture, then drizzle in 1/3 of milk and sour cream mixture. Beat at low speed until just blended after each addition. Repeat adding in increments, beginning and ending with flour mixture. Use a flexible spatula to scrape bowl, if necessary, and beat at low speed until combined, about 1 minute. Divide batter equally between baking cups, filling each about 2/3 of the way.

Bake until a wooden toothpick or cake tester inserted into center of cupcakes comes out clean and cupcakes spring back lightly when touched, about 18 minutes. Transfer to a wire rack. Let cool in pan for 10 minutes, then remove cupcakes from pan and allow them to cool completely on wire rack, about 15 minutes.

Using a flexible spatula, scrape buttercream into prepared piping bag. Pipe buttercream on top of each cupcake until completely covered. (Alternatively, use an offset spatula to spread buttercream on top of each cupcake until completely covered.) Repeat with remaining cupcakes.