Preheat your oven to 350. Heavily spray a 9 x 13 inch pan with cooking spray and set aside.
Prepare the Sugar Cookie mix as you would for making just regular cookies (as opposed to cut out cookies).
Mix in the pudding mix (just the dry mix) and the M&Ms.
Push the dough into the pan and bake for 15 minutes or until the edges turn golden brown.
Let the bars cool completely before cutting into them, or just go nuts and eat the pan with a spoon.