First line a 9×13 baking pan with aluminum foil and then butter the pan, or you can use non-stick foil.

Next place all of the chocolate chips, butterscotch chips and peanut butter in a large, microwave safe bowl. Microwave in 30 second increments, stirring after each, until completely melted and smooth.

If you prefer to use a stove top instead of a microwave you can place the chocolate chips, butterscotch chips and peanut butter in a large saucepan over low heat. Stir frequently until all of the chips are completely melted and smooth. Remove from heat.

Add marshmallows into the melted chocolate chip mixture and stir until the marshmallows are evenly coated.

Pour the mixture into the prepared pan and spread it out evenly.

Sprinkle M&M’s evenly across the top of the marshmallow mixture.

Place in the refrigerator for at least 2 hours until completely set.

Remove from refrigerator and allow to sit for about 10 minutes before cutting. Cut into 24 squares and serve.