Sprinkle grated chocolate onto a plate. Moisten the rim of a martini glass with water; hold glass upside down and dip rim into chocolate. Place cherry in glass. If desired, garnish glass with chocolate syrup.
Fill a tumbler or mixing glass three-fourths full with ice. Add the cream, vodka, chocolate liqueur and creme de cacao; stir until condensation forms on outside of tumbler. Strain into glass; serve immediately.
Editor's note: To coat the edge of the glass rim with grated chocolate, dip the rim in water, then in the grated chocolate.