Line an 8-inch pan with foil and generously grease it with butter or cooking spray.

Melt chocolate chips, peanut butter, and margarine for about 1 minute in the microwave.

Add marshmallows and mix.

Pour into a greased 8-inch pan and put in the fridge for about 2 hours. If you need this quick, put in the freezer for about 45 minutes.

Cut into 1-inch squares and enjoy!