In a large mixing bowl add, butter, peanut butter, sugar, brown sugar, vanilla and eggs. With an electric mixer or stand mixer, cream together for about 1 minute, until the sugars are well combined and the batter is fluffy and soft.
Add in the flour, salt, baking soda and quick oats. Continue to mix with the electric mixer until well combined and a thick cookie dough is formed.
Fold in the chocolate chips and M&M candies with a wooden spoon or mix in with the mixer until fully incorporated into the cookie dough.
Press the cookie dough evenly into a 12 inch cast iron pan or 9x13 inch baking dish
Bake for 18-20 minutes, until golden on the edges and still a little soft in the center.
Video
Notes
Nutrition facts are just an estimate
This recipe can be baked in a 12 inch cast iron pan or 9x13 inch baking dish