Marshmallow creme is the key to these ooey-gooey cookie bars. The hardest part is waiting for them to cool!
For a more decadent bar, drizzle top of bar with chocolate-flavor syrup before serving.
You can find graham cracker crumbs in the baking aisle of your grocery store.
To make your own graham cracker crumbs, place 16 graham cracker squares in food processor. Cover; process, using on-and-off pulses, until fine crumbs.