Spray a 9x13 baking pan with non-stick baking spray and set aside.

In a large microwave safe bowl, melt the butter in the microwave for about 1 minute, or until melted. Stir in the marshmallows, microwave for another 1-2 minutes, stirring every 30 seconds until marshmallows are melted.

Stir in peanut butter cereal until all is coated in the marshmallow butter mixture. Pour into the prepared pan, and press down with a spatula until evenly spread. Sprinkle with mini chocolate chips, press gently so they stick. Cool and chill completely before cutting and serving. I like them served cold from the fridge!