Preheat oven to 350°F. Line muffin tins with paper liners.
Melt chocolate with hot coffee; let cool.
Whisk flour, baking soda, and salt.
Cream butter and sugar until fluffy (3-4 minutes).
Beat in eggs one at a time, then vanilla and chocolate mixture.
Alternate adding flour mixture and buttermilk to batter.
Fill cupcake liners ⅔ full.
Bake 18-20 minutes until done.
Cool completely before frosting.