Line a 9x13” pan with foil and spray with nonstick cooking spray.

Place butter, peanut butter, marshmallows, and chocolate in a large bowl. Heat in 30 second increments, stirring between each, until the mixture is melted. Quickly stir in the rice krispies. If the mixture starts to seize, add 1-2 tablespoons more of butter.

Press into prepared pan. Let them cool, then cut into squares.

Place about 1 cup powdered sugar in a bowl and coat each square with powdered sugar. Serve.

Store in an airtight container for up to 3 days.