Preheat the oven to 350 F. To make the cookie dough, combine the granulated sugar, brown sugar, and room temperature butter in the bowl of a stand mixer. Cream together for 4-5 minutes, scraping the bowl’s sides as necessary to bring the mixture down to the bottom.
Add the eggs, one at a time. Beat the mixture on medium speed until each one is incorporated.
Add the peanut butter, baking soda, and vanilla extract. Beat well on medium speed until combined.
Add the oats, mixing on low speed until combined.
Next, add the chocolate chips, mixing on low speed until combined.
Prepare a rimmed quarter baking sheet with nonstick cooking spray. Pour the dough onto the baking sheet and spread the dough evenly with an offset spatula. Top the cookie dough with the candy-coated chocolate pieces.
Bake for 18 minutes or until the monster cookies are puffed, golden on the edges, and cooked through.
Tips
Use a brand of candy-coated chocolates that are naturally colored that also uses less sugar for monster cookie bars that are perfectly sweet.
Be sure to use quick oats because, as they cool, they set the cookie bars.
