Preheat your oven to 350f

Line a 8x8" baking pan with aluminum foil, and grease with a non stick cooking spray

In a large mixing bowl beat together your butter and sugar until light and fluffy

Then mix in your egg, peanut butter, and vanilla extract

Now mix in your flour until you have a thick dough

Fold in one cup of your M&Ms and press your cookie dough into your baking pan

Press the rest of your M&M's into the top of your bars and bake for 20-25 minutes

Let cool and lift up aluminum foil to remove your bars

Cut into nine squares and carefully cut all sides off of the bars

ENJOY!