Instructions

1. Preheat the oven to 375 F (190 C). Position an oven rack in the center position.
2. In the bowl of a stand mixer fit with a paddle attachment (or large mixing bowl with a hand mixer) cream the butter, peanut butter and brown sugar together on medium/high speed until light and fluffy. This should take about 3-5 full minutes.
3. Scrape down the sides and the bottom of the bowl. Add the egg and vanilla and continue mixing on medium speed until just incorporated.
4. In a separate mixing bowl, whisk together the flour, baking powder, baking soda, salt, and quick oats. You want to use quick oats for the best texture of the cookies. If you only have rolled oats, pulse them in a food processor a few times until they are a bit smaller. If you do not have this option, you can use the rolled oats as is, but be aware the cookies will not spread quite as much and the texture will be a little different.
5. Add the dry ingredients into the mixing bowl and mix until they are just incorporated. You do not want to overmix or your cookies will become tough.
6. Take the mixing bowl off of the mixer and use a rubber spatula to fold in the chocolate chips and M&M's.
7. Use a large cookie scoop (or a spoon) to form large dough mounds. I think these work best with about 3 TBSP worth of dough per cookie. I use a 2 oz scoop that is not filled all the way.
8. Top each dough mound with a few more chocolate chips and M&M's to give a nice appearance after baking. You can also sprinkle a little flaky salt over the top if you like.
9. Bake 1 cookie sheet at a time for 8-10 minutes. Pull them from the oven when the edges are set and the centers still look slightly under baked. Allow to cool on the cookie sheets. This will let them finish cooking and set the cookies.
10. Store cooled cookies at room temperature in an airtight container for up to 1 week.