Preheat your oven to 350 degrees Fahrenheit.
In a medium mixing bowl, add in butter, granulated sugar, light brown sugar and peanut butter. Using a mixer, mix on medium speed until combined and creamy.
Add in the eggs & vanilla, mix again until fully incorporated.
Add in the flour and baking soda, mix on low until combined. Do not over mix.
Next add in the oats, mix until combined.
Using a spatula or wooden spoon, fold in the M&Ms & chocolate chips until combined.
Scoop cookies into 2 tablespoon size balls, place onto a baking sheet 2” apart.
Using a fork, slightly flatten each cookie.
Place on the center rack in the oven and bake for 10-12 minutes or until the edges are golden brown.
Let cool on the baking sheet for 2 minutes. Before removing from the cookie sheet, press in a few M&Ms to the tops of the cookies. Then, transfer to a baking rack so cookies can continue cool.
Serve & enjoy!