1. To make the cupcakes. Preheat oven to 350° F. Line cupcake molds with paper liners (24-26).2. In a large bowl, beat together the oil, eggs, milk, yogurt, sugar, and vanilla. Add the flour, cocoa powder, baking powder, baking soda, and salt. Mix until just combined, then slowly beat in the coffee until combined. It will be thin. If using, stir in mini-chocolate chips.3. Divide the batter evenly among the prepared cupcake molds. Bake 25-30 minutes, until the tops are just set, and no longer wiggly in the center. Remove and let cool.4. To make the frosting. In a large bowl, beat the butter until light and fluffy, about 2-3 minutes. Add the powdered sugar and beat to combine. Pour in the melted chocolate, vanilla, and 1 tablespoon warm milk. Beat until fully combined and whipped. If needed, thin with milk. 5. Frost each cupcake, then decorate as desired with sprinkles and or chocolate shavings.