Add butter, peanut butter and milk chocolate chips to a heavy sauce pan or Dutch oven and place over medium heat. Stir until melted, add marshmallows and continue to stir until melted.
Remove from heat and add cereal. Stir until well coated and throughly mixed.
Spread evenly into a 8 X 13 -inch pan.
Allow to cool completely.
Chop peanut butter cups and sprinkle over Rice Krispie Treats.
In a small microwave-safe bowl, add 1/3 cup milk chocolate chips and milk. Microwave about 20 to 30 seconds and stir until smooth. Continue to cook in 15 second intervals, stirring in between until smooth and melted.
Drizzle over peanut butter cups and Rice Krispie Treats.
Allow to cool and cut into bars.