Vanilla-frosted Chocolate Cupcakes

Position oven rack in the center of the oven. Preheat oven to 350º F / 180º C. Line a muffin tin 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 muffin 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 Vanilla Buttercream Frosting:

In the bowl of a standing mixer fitted with a whisk, mix together sugar and butter. Mix on low speed until well blended; increase speed to medium and beat for an additional 3 minutes.

Add vanilla and cream one tablespoon at a time and continue to beat on medium speed for and additional minute or two, adding more cream if needed until desired consistency is achieved.