Preheat the oven to 350°F (175°C) and line a muffin pan with cupcake liners.Whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.Add the eggs, oil, milk, and vanilla, mixing until smooth.Slowly stir in the hot coffee until the batter is thin and fully combined.Fill each cupcake liner about two-thirds full.Bake for 18–20 minutes, or until a toothpick inserted into the center comes out clean.Cool the cupcakes in the pan for 5 minutes, then transfer to a wire rack to cool completely.Beat the butter until fluffy. Gradually mix in the powdered sugar, cocoa powder, vanilla, salt, and cream until smooth.Pipe or spread the frosting onto the cooled cupcakes.Decorate with chocolate sprinkles, shaved chocolate, or mini chocolate chips if desired.
