Place chocolate in a medium bowl. Microwave heavy cream for 1 min, until just steaming. Whisk 1 generous drop black gel food coloring into cream and pour over chocolate. Let stand 2 min, then whisk until smooth.Advertisement
Meanwhile, whisk 1 cup plus 2 tbsp confectioners' sugar and 2 tbsp milk in a bowl. Whisk 1 1/4 cups confectioners' sugar and 2 tbsp milk in another bowl and add 1 drop black gel food coloring.
Dip 8 doughnuts in chocolate and sprinkle with black sugar. Dip 8 doughnuts in gray frosting and sprinkle with silver sugar. Dip 8 doughnuts in white frosting and top with jimmies. Let dry. Makes 24.