MICROWAVE marshmallows and butter in large microwaveable bowl on MEDIUM 2 min. or until marshmallows are puffed; stir until marshmallows are completely melted and mixture is well blended.
ADD chocolate; stir until melted. Stir in remaining ingredients. (Mixture will be thick.)
SPREAD into greased 9x5-inch loaf pan. Refrigerate 1 hour or until firm.
serving size = 1 piece (26 g)