Chocolate Frosted Yellow Cupcake

Yields 2 8-inch or 9-inch cake rounds

4 cups cake flour
2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 teaspoon salt
1 cup (2 sticks) unsalted butter, room temperature
1 1/2 cups sugar
2 teaspoons pure vanilla extract
4 large eggs, room temperature
2 cups buttermilk

Preheat oven to 350 degrees F. Grease and flour 2 8 or 9-inch round cake pans.

In a medium bowl, sift together the flour, baking powder, baking soda, and salt.

In a large mixing bowl, cream together the butter and sugar with a mixer at medium speed until the mixture is light and fluffy. Beat in vanilla. Add the eggs one at a time, mixing thoroughly after each addition. Turn the mixer to low and beat in the buttermilk until just combined. The mixture will look curdled. Add the flour mixture in three separate batches, beating just until each addition is fully incorporated.

Spread the batter evenly between the prepared cake pans. Bake for 35 to 40 minutes, or until the tops are golden brown and a toothpick inserted in the center of the cake comes out clean (if using 8 inch cake pans, add 5-10 minutes to the baking time but watch closely). Remove from the oven and cool in the pans for 10 minutes. Run a knife around edge of pan and invert onto a cooling rack. Cool completely before frosting, about 1 hour.

Chocolate Frosting
Adapted from here

Yields enough frosting to cover a 2 layer 8 or 9-inch cake

1/2 cup butter, room temperature
2 1/4 cups powdered sugar
2/3 cup cocoa powder
1/2 teaspoon vanilla extract
1/4 cup milk

In a large mixing bowl, cream the butter until it is smooth without lumps. Gradually add the powdered sugar, cocoa, and vanilla extract. Scrape down the sides of the bowl as needed. Lastly, add the milk until the frosting reaches a spreadable consistency.