1. Preheat oven to 325 degrees and line cookie sheets with parchment.

2. Using a stand mixer or hand beaters, beat butter, brown sugar and granulated sugar together until creamy. (About 2 minutes.)

3. Add in egg, egg yolk and vanilla extract. Beat a little after each addition.

4. In a separate bowl. whisk together flour, oats, baking powder, baking soda and salt.

5. Add dry ingredients slowly to the butter/sugar mixture and mix only unit just combined.

6. Add in chocolate chips and 1 cup M&M's and stir just until distributed evenly.

7. Scoop out cookie dough balls about the size of a golf ball (maybe a tad bigger) and use the extra 1/3 cup M&M's to stud the dough balls with extra M&M's. This way, when they bake you'll have some candies on the outside that make them look bakery perfect. (See cookie dough ball photo.)

8. At this point you can either freeze the dough balls for 30 minutes or you can bake them right away. I prefer freezing my dough first.

9. Bake for 15-20 minutes depending on how soft or crispy you want your cookies!

10. Serve with milk for the perfect after school (or work) treat!