In custard cup, sprinkle gelatin over cold water; let stand 1 minute to soften. Add boiling water; stir until gelatin is completely dissolved and mixture is clear. Cool slightly. In small bowl, stir together sugar and cocoa; add whipping cream and vanilla. Beat at medium speed, scraping bottom of bowl occasionally; until stiff peaks form. Pour in gelatin mixture and beat until well blended. Spoon into serving dishes. Chill about 1/2 hour. For variety add a dash of rum, Kaluha or instant coffe crystals while beating mixture. Serves 4.
