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Monster Mash Cookies

Soft and chewy peanut butter cookies with nutty oats, M&Ms, semi-sweet chocolate, and salty pretzels to finish—they're such a simple treat and are perfect to make for the Halloween season!
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Course: Dessert
Keyword: cookies
Servings: 18 cookies
Author: Mae Martin

Ingredients

  • 10 tablespoons unsalted butter*
  • ½ cup smooth peanut butter, such as JIF**
  • ½ cup light brown sugar
  • ¼ cup granulated sugar
  • 1 egg
  • 2 teaspoons vanilla extract
  • 1 cup all-purpose flour
  • ¾ cup old-fashioned oats
  • ½ teaspoon baking soda
  • ½ teaspoon kosher salt
  • ½ cup M&Ms
  • ¼ cup mini pretzels
  • ¼ cup semi-sweet chocolate chips

Instructions

  • Cut the butter into cubes and place in a large saucepan. Set the pan over medium heat and stir until melted. Continue to stir the butter every ten seconds or so, until it bubbles and begins to foam. Once you see brown bits floating in the butter and a nutty aroma is released, immediately remove the pan from the heat.
  • Pour the butter into a bowl to stop the cooking process, making sure to get all the browned bits from the bottom of the pan. Allow the butter to cool to room temperature, or set it in the fridge for around 30 minutes to speed up the process.
  • In the meantime, mix together the flour, oats, baking soda, and cinnamon in a medium bowl until well combined. Set aside.
  • When the butter is cooled, pour it into a large bowl with the peanut butter and whisk until smooth. Add the brown sugar and granulated sugar and mix for 1-2 minutes. Beat in the egg and vanilla.
  • Once the wet ingredients are well mixed, add in the dry ingredients, M&Ms, pretzels, and chocolate. Stir the mixture together until a dough forms (be careful not to overmix). If the dough is too sticky, add 1-2 tablespoons more flour---you should be able to pinch a bit of dough without getting a lot of sticky residue on your fingers.
  • Scoop the dough onto a baking sheet lined with wax or parchment paper. Cover the tray with plastic wrap and refrigerate for at least 30 minutes but up to two days. At this point, the cookie dough can be frozen.1
  • Preheat the oven to 375℉ and line a baking sheet with parchment paper.
  • When ready to bake, evenly space the cookie dough balls onto the baking sheet with a 2'' gap between each cookie. If desired, press the top of the dough with more M&Ms and pretzels.
  • Bake for 10-12 minutes, rotating the tray halfway through. Remove the cookies from the oven once the edges are golden brown and set, but do not overbake (they will set more as they cool). Once out of the oven, sprinkle the cookies with flaky salt and allow to cool before serving.

Notes

*If you don't want to brown the butter, simply substitute with 8 tablespoons of cooled, melted butter.
 
**Be sure to use a brand like JIF or Skippy. Natural peanut butter made from just peanuts and salt will not work in this recipe.
  1. If you plan on refrigerating the cookie dough, I recommend scooping it beforehand. Otherwise, the dough will harden and become too difficult to scoop. To freeze, portion the cookie dough onto a baking sheet and place it in the freezer for 1 hour. Once firm, store the dough balls in a plastic bag in the freezer for 3-6 months. To cook, follow the baking instructions as written (no need to thaw the dough), though the cookies may need a couple of more minutes to cook.