• Spoon teaspoon-sized dollops of the peanut butter onto a parchment paper-lined plate. Freeze until solid, about 30 minutes.

Make the Cookie Dough:

• Preheat the oven to 350ºF, and grease a 10-inch cast iron skillet with butter or nonstick cooking spray.
• In a large bowl, whisk the flour, baking soda, baking powder, salt, and oats together; set aside.
• In a stand mixer fitted with the paddle attachment, cream the butter and both sugars together until light and fluffy, about 3 minutes.
• Mix in the peanut butter until smooth. Add the eggs, one at a time, followed by the vanilla. Scrape down the sides of the bowl with a rubber spatula as needed.
• Slowly incorporate the flour mixture into the wet mixture. Stir in 3/4 cup of the M&M's and 3/4 cup of the chocolate chips by hand.
• Press half of the cooking dough into the bottom of the cast iron skillet. Place the frozen dollops of peanut butter evenly over the dough. Cover with the remaining dough by pressing portions of dough between your palms, then piecing them together on top of the peanut butter. Make sure all of the peanut butter is covered.
• Bake for 28-32 minutes, or until the edges are lightly golden and the center is set. Immediately, press remaining 1/4 cup M&Ms and 1/4 cup chocolate chips into the top of the pizookie.
• Allow to cool for at least 30-40 minutes. Slice and serve with a scoop of ice cream, if desired.