cupcakes:
3/4 cup butter
3 eggs
1 3/4 cups all-purpose flour
1 cup unsweetened cocoa powder
1 teaspoon baking soda
3/4 teaspoon baking powder
1/2 teaspoon salt
1 cup milk
1/2 cup strong brewed coffee, cooled
2 cups sugar
2 teaspoons vanilla
1 cup dark, bittersweet, or semisweet chocolate pieces
1 recipe Coffee Buttercream
30 creme-filled rolled wafer cookies, such as Pirouettes (optional)
Unsweetened cocoa powder or ground cinnamon (optional)

buttercream:
1/3 cup butter
4 cups powdered sugar
3 tablespoons strong brewed coffee, cooled
1 teaspoon vanilla
Strong brewed coffee, cooled (optional)