adapted from: One Dirty Bowl
1 (16 oz.) pkg. refrigerated sugar cookie dough (the flat sheet, not the roll)
1 (12 oz.) bag assorted miniature candy bars, unwrapped
or 3 (6-pack) pkgs. fun-size candy bars, chopped
16 large marshmallows, cut in half
or 3 cups mini marshmallows
Preheat oven to 350 degrees. Spray an 8x8-inch baking dish with cooking spray and line with parchment paper with a slight overhang (to help easily remove the bars for cutting). Place the cookie dough, as a block, into the baking dish. It won't fill the whole pan, but will spread out as it bakes. Bake for about 30 minutes or until the edges are lightly browned and the center is almost set.
Remove pan from oven and top with candy bars, covering every last bit of the cookie crust. Top chocolate layer with marshmallows. Return to oven and broil on low for 3-5 minutes or until the marshmallows are lightly toasted. Remove from oven and allow to cool for at least 20 minutes before serving (I let mine cool for about an hour and they were still extra ooey gooey).