Pre-heat the oven to 350°F. Line two baking sheet with parchment paper or Silpat baking mats.
In the bowl of a stand mixer fitted with the paddle attachment, cream together the sugar, brown sugar and butter until light and fluffy.
Beat in the eggs, one at a time, and then beat in the peanut butter, vanilla, baking soda and salt until well combined.
Add the the oats and mix until combined, then add the mini M&Ms and mini-chocolate chips.
Scoop 2-to 3-tablespoon mounds of the dough onto the prepared baking sheets, spacing the mounds at least 2 inches apart.
Bake the cookies for 12-15 minutes then remove them from the oven and allow them to cool for 5 minutes on the baking sheets before transferring them to a rack to cool completely.