Line a 9x13 inch pan with foil and grease with cooking spray.

Cover the bottom of the pan with about 1 package of graham crackers.

Crush 1 cup of the graham crackers. I used about 1 package of the graham crackers.

Combine butter, brown sugar, granulated sugar, evaporated milk and graham crackers in a saucepan.

Bring to a boil and continue boiling for 5 minutes, stirring constantly.

Pour the caramel mixture over the crackers in the pan.

Break Hershey's bars into small pieces and place in the caramel sauce.

Cover with another layer of about 1 package of graham crackers.

Spread the Nutella over the graham crackers.

Top with mini marshmallows.

Toast under broiler for about 2 minutes, watching carefully so marshmallows don't burn.

Allow the bars to cool completely before cutting into squares.