Preheat oven to 375°F
Beat butter and peanut butter.
Add sugars, vanilla, and egg until smooth.
Add flour, oats, salt, baking soda, and cornstarch. Mix all.
Fold in M&Ms, chocolate chips, peanut butter chips, and chopped peanut butter cups.
Form 4 ounce mounds. Can bake 6 at a time. Roll into balls and poke to create texture.
Bake for 12–13 mins, remove and add more goodies on top.