Preheat your oven to 350°.
In a large bowl, beat the butter and sugar for a minute. Add the eggs, sour cream and coffee and mix until combined. Add the remaining cake ingredients and beat for 1-2 minutes until smooth and only a few lumps are visible.
In lined cupcake pans, fill each cup 3/4 full. Bake at 350° for 25-30 minutes until a toothpick inserted in the center of the cupcake comes out clean. Set aside and allow to cool completely.
Meanwhile, in a large bowl, beat the butter and shortening for 3-4 minutes until smooth and lightened a bit in color. Add the vanilla, and 1/3 of the powdered sugar and beat for 2-3 minutes. Add half of the remaining powdered sugar and beat for an additional 2-3 minutes. Add the remainder of the powdered sugar and beat the buttercream until it is light and fluffy.
Pipe or spread the buttercream on the cooled cupcakes and top with a chocolate covered espresso bean. Store in an airtight container.