Roughly chop the chocolate. Heat the cream in a small pot, dissolve the chocolate in it while stirring. Keep warm. Wash the grapes, dab dry. Pluck the grapes from the panicles. Cut off the flesh of the mango directly at the stone.
Score the flesh of the fruit crosswise on the skin, pressing the skin inwards. Cut the flesh cubes from the skin. Arrange chocolate sauce in bowls, fruit, marshmallows and biscuits on plates or in bowls.