1in food processor, combine graham crackers and butter. Process until crumbs form moist clumps. Press mixture onto bottom of a 9 inch springform pan. Freeze crust one hour.
2Spoon ice cream into large bowl. Stir in chocolate chips. Spread evenly over crust. Freeze two hours.
3Spoon marshmallow cream into bowl. Add half of the marshmallows and stir until combined. Spread evenly over ice cream. Scatter remaining marshmallows on top, gently pressing down. Cover and freeze cake at least one day or up to two weeks.
4To serve, cut around edge of ice cream and pan to loosen. Remove sides of pan. Rub thin metal spatula under bottom of crust to loosen cake. Transfer to cake platter. Using a small kitchen torch, carefully toast marshmallows on top of cake until lightly golden. Serve at once. Serves 12