These are from Betty Crocker.  They have a sugar cookie/graham cracker crust with a layer of fudge and toasted marshmallows on top.  

Crust – 1 pkg sugar cookie mix, 1 cup of graham cracker crumbs, 1 stick of butter (melted).  

Combine and press in ungreased 8×8 pan.  Bake 350  in a preheated oven for 18 to 23 minutes.  Let cool.

Fudge layer – 2 cups of chocolate chips, 14 oz condensed milk.

Microwave in 45 second intervals until you can stir it smooth.  Place on top of crust.  Chill 1 hour.

Sprinkle with mini marshmallows.

Broil on high for one minute.

Let stand 1 hour.  Cut with a knife that has been run under hot water and wiped off.  That makes it easier to cut.  (You will have to do the water thing a few times)