Set butter out to soften.
In a stand mixer or in a large mixing bowl with a hand mixer, cream all the peanut butter, butter, sugar and packed brown sugar. Stir in the vanilla and 2 eggs.
Stir in the flour, baking soda, baking powder, salt and mix into dough. Stir in the quick cooking oats and mix into dough again.
Add the peanut butter chips, chocolate chips and M&Ms and gently stir them in. Chill the dough in the refrigerator for at least 2 hours.*
Preheat the oven to 350 F. Line a baking sheet with silicone baking mat.
Mix the dough to loosen it up some and then stir in the crushed pretzel pieces. Scoop the dough with an ice cream scooper and place on the baking sheet.
Bake in the preheated oven for 9-11 minutes, or until cooked through.
Let cool slightly on cooling rack before serving.
Serve Peanut Butter Monster Cookies.