M&M's Marshmallow Dream Bars

M&M's Marshmallow Dream Bars 12 oz package semi-sweet chocolate chips 11 oz package butterscotch chips 1 cup creamy peanut butter 10.5 oz bag mini marshmallows 1 cup M&Ms Line a 9x13 baking dish with non-stick foil. Set aside. Combine first three ingredients in a large microwave safe container. Microwave on high heat in 30 second intervals, stirring in between, until the chips are fully melted and the mixture in smooth. Stir in marshmallows until fully coated. Pour mixture into prepared baking dish. Sprinkle on M&Ms and press down slightly. Refrigerate until set, about 2 hours. Cut into bars. Store leftovers in an airtight container.