Preheat oven to 350 degrees F (175 degrees C). Prep your cupcake liners.
Sift together dry ingredients ( flour, cocoa, baking soda and salt.) Set aside.
In a medium bowl, cream butter and sugar until light and fluffy. Add egg and vanilla and beat well. Add flour mixture, alternating with coffee. Beat until just incorporated.
Bake at 350 degrees F (175 degrees C) for 10-15 minutes or until toothpick inserted comes out clean. You'll have to watch this carefully since they aren't as full as normal cupcakes!