Double Chocolate Cupcakes

Position oven rack in the middle. Preheat oven to 350º F / 180º C. Line muffin pans with paper or foil liners.

Using an electric mixer set on high speed, cream together the butter and sugars, until light and fluffy, about 5 minutes. Lower the speed to medium, add the vanilla and the eggs one at a time and mix well.

In a separate bowl, whisk together the buttermilk, sour cream, and coffee. Using a new bowl, sift together the flour, cocoa powder, salt and baking soda. With the mixer on low speed, starting with the buttermilk mixture and ending with the flour mixture, add alternately in thirds to the butter and sugar mixture. Mix until just blended, scraping the sides with a rubber spatula to completely incorporate.

Divide batter evenly between lined cups, filling each cup three-quarters full. Bake for 20 to 25 minutes or until a cake tester inserted in the middle comes out clean. Rotate tins halfway through the baking process to promote even baking. Cool for 10 minutes in pan. Remove cupcakes from pan and transfer onto wire racks to cool completely before frosting.

For Chocolate Buttercream Frosting:

In a medium bowl, using a mixer with the paddle attachment on medium speed, cream butter for about 2 minutes.

Sift 3 cups confectioners' sugar and cocoa into the mixing bowl. With the mixer set on the lowest speed, mix the dry ingredients until they are absorbed by the butter. Increase mixer speed to medium and add vanilla extract, salt, and milk; beat for about 3 minutes. If the frosting is to thin, add additional confectioners' sugar, 1 tablespoon at a time. If the frosting needs to be thinned out, add additional milk 1 teaspoon at a time.