Use refrigerated sugar cookie dough. Roll out the dough, place your chocolate on the dough and marshmallows then place another piece of dough over the top and "crimp" the edges. Add a sucker stick if you want. Bake using cookie dough instructions.
I love Despicable Me! I've only watched the first one so far and the second one kinda sucked and the minion movie will probably drain the life out of the franchise entirely, but I still love me some minions!