Preheat oven to 325°. In a small bowl, combine cracker crumbs and sugar; stir in butter. Press onto the bottom and up the sides of a 7-in. pie plate coated with cooking spray. Bake 7-9 minutes or until lightly browned. Cool on a wire rack.
Carefully spread ice cream into crust; freeze until firm. Spread marshmallow creme over ice cream. Top with marshmallows; gently press into creme. Cover and freeze 4 hours or overnight.
Just before serving, broil 6 in. from the heat for 1-2 minutes or until marshmallows are golden brown.