1/2 c unsalted butter, melted, cooled
1 pkg devils food cake mix
3/4 c creamy peanut butter, warm
16 large marshmallows, quartered
Preheat oven to 350F. Combine butter and dry cake mix in a bowl until crumbly. Reserve 1-1/2 cups of mixture. Pat remaining crumb mixture into an ungreased 9x13 inch pan. Combine peanut butter and marshmallows in a bowl. Spread evenly over crumb mixture in the pan. Crumble reserved cake mixture over top and bake 20 minutes. Let cool before cutting into bars.