1st layer: in a double boiler or metal bowl over simmering water, stir until melted and smooth. Line a greased 8 x 11.5 inch baking dish with plastic wrap. Pour fudge into baking dish. Cool until room temp, place in the refrigerator while you make make the peanut butter fudge.
2nd layer: Combine peanut butter chips, 1 can sweetened condensed milk and 2 T butter in a double boiler or metal bowl over simmering water, stir until melted and smooth. Pour onto the milk chocolate fudge layer and press Reece's Peanut Butter Cups into the fudge. I left a small space between them for a 'cutting line'. Let cool until room temperature. Refrigerate overnight or until set. Remove from refrigerator and cut into squares(1 peanut butter cup per square) and serve. Keep refrigerated or they will get too soft. The milk chocolate doesn't set up as solid as semi-sweet chocolate.
to remove from baking dish, lift the plastic wrap from the sides and it should come right out.