Turn oven on to broil. Line small baking sheet with foil. Slice banana in half lengthwise and crosswise to create 4 pieces. Remove skins and place onto baking sheet. Cut marshmallows into discs and place on top of banana slices. Put under broiler and toast marshmallows until lightly toasted. Set banana slices into a shallow bowl and add in pieces of graham cracker in between banana. Drizzle with hot fudge and top with scoops of ice cream. Drizzle any more hot fudge onto ice cream if desired and top with cream. Serve immediately.