Cream the butter and sugar together really well—at least 2-3 minutes until light and fluffy.
Add peanut butter and mix well. Add egg and vanilla and mix.
In a separate mixing bowl stir together the flour (be careful to measure correctly, spooning the flour into a measuring cup, then leveling off), oats, salt, baking powder and baking soda.
Add to the wet mixture and mix to combine. Stir in chocolate chips and M&M’s.
Bake at 350 degrees for 10-12 minutes, or a little longer if you make them bigger than a 1 inch cookie scoop. Don't over bake--they will look just set.
Remove them from the oven and allow them to cool completely on the pan.
Video
Notes
Adapted from our Mrs. Fields chocolate chip cookie recipe.