Preheat oven to 350 degrees F. Line baking sheet with parchment paper.
In a large bowl, cream together butter and sugars on medium speed for about 3 minutes.
Mix in the peanut butter, egg and vanilla, mixing after each addition, scraping down the sides of the bowl as needed.
Slowly mix in the baking soda and flour. Do not overmix.
Fold in the quick oats, M&Ms and chocolate chips.
Rolls into balls, about 1 Tablespoons of dough per ball, onto prepared baking sheet. If the dough is very soft and unmanageable by hand, chill the dough for 30 minutes before rolling.
Bake for 8 minutes. The cookies will appear undone. Slightly press down the baked cookies with the back of a spoon, since the cookies only slightly spread in the oven.
Allow cookies to cool on baking sheet for 10 minutes before transferring to a wire rack. Cookies will firm up as they cool. Store cookies covered at room temperature for up to 1 week. Cookies freeze well.
