01 -
Melt the butter in a large saucepan over medium heat. Add the peanut butter and stir until well combined.
02 -
Add the mini marshmallows, stirring constantly until the mixture is smooth. Remove from heat.
03 -
Stir in the Rice Krispies cereal, making sure each piece is evenly coated.
04 -
Gently fold in the halved mini peanut butter cups.
05 -
Lightly grease a 9x13-inch pan and press the mixture into an even layer.
06 -
Allow the treats to cool to room temperature. Optionally, drizzle with melted chocolate before slicing into squares and serving.