In the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter, granulated sugar and brown sugar until fluffy.
Beat in the eggs, peanut butter and vanilla, scraping the sides of the bowl as needed.
In a large bowl, whisk together the flour, baking powder, baking soda and salt.
With the mixer running on low speed, add the dry ingredients into the wet ingredients alternately with the oats. Fold in the mini M&Ms and chocolate chips.
Chill the cookie dough for at least 30 minutes.
Preheat the oven to 350F degrees. Line two baking sheets with parchment paper.
Use a 3 Tbsp. cookie scoop to portion out the dough. Place unbaked cookies at least 2 inches apart on the baking sheets. Bake 14-16 minutes. Cool cookies on the baking sheets before transferring to a wire rack.