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M&M Oatmeal Monster Cookie Sandwiches

These M&M oatmeal monster cookie sandwiches are the perfect way to use up extra seasonal M&M candies! Or, make them just because! Between each soft-baked oatmeal monster cookie is a scoop of silky cream cheese frosting for an extra special treat!
Prep Time 45 minutes
Cook Time 10 minutes
Cooling and Frosting Time 1 hour
Total Time 1 hour 55 minutes
Course Dessert
Cuisine American
Servings 18 cookie sandwiches

Ingredients
  

For the M&M Oatmeal Monster Cookies

  • 3/4 cup unsalted butter (1½ sticks at room temperature)
  • cups brown sugar
  • 1 large egg (room temperature)
  • 2 tsp vanilla extract
  • cups all-purpose flour
  • ½ tsp baking soda
  • ½ tsp baking powder
  • ½ tsp salt
  • 2 cups old fashioned oats (uncooked)
  • 2 cups M&M's

For the Cream Cheese Frosting

  • 4 oz full fat cream cheese (room temperature)
  • ½ cup unsalted butter (room temperature)
  • 3½ - 4 cups powdered sugar (depending on the thickness you want!)
  • 1 tsp vanilla extract
  • 1/2 tsp salt

Instructions
 

For the M&M Oatmeal Monster Cookies

  • For high altitude instructions, see "Notes" section below.
  • Preheat oven to 325°F. Line large baking sheets with parchment paper and set aside.
  • In the bowl of a stand mixer fitted with a paddle attachment, or in a large bowl with a hand mixer, beat the butter and sugar on medium-high speed until light and fluffy (about 2 minutes).
  • Add the egg and vanilla and beat until well incorporated (about 1 minute).
  • Add the flour, baking soda, baking powder and salt. Mix on low speed until just combined, but do not overmix. Scrape down the sides of the bowl with a spatula as needed.
  • Add the oats and mix on low speed until just combined. Fold in the M&M's until just combined, but do not overmix.
  • Using a 1 tablespoon cookie scoop, create cookie dough balls and place on a plate or baking sheet and chill in the refrigerator for 30 minutes or overnight.
  • Remove cookie dough balls from the refrigerator and place on prepared baking sheets, leaving 2 inches between each cookie.
  • Bake for 10 - 11 minutes, or until the edges are browned and the centers are set. Remove baking sheet from oven and cool cookies in the pan for 5 minutes on a wire rack. Remove cookies from pan and finish cooling on wire rack.

For the Cream Cheese Frosting

  • In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl with a hand mixer, beat the butter and cream cheese on medium-high speed until combined. Add in the vanilla and salt and mix until combined.
  • Slowly add the powdered sugar and mix on low speed until combined. Increase mixer to medium-high speed and beat until light and fluffy.
  • If frosting is too thick, add milk 1 tablespoon at a time until desired consistency is reached.
  • Using a 1 tablespoon cookie scoop, place dollops of frosting onto a cooled cookie, and then sandwich using another cookie. Squeeze until frosting reaches the edges of the cookie. Repeat with remaining cookies and enjoy!

Notes

If you have leftover cream cheese frosting, place in an airtight container and store in the freezer for up to 3 months.
Cookies can be stored in an airtight container in the refrigerator for up to 5 days.
High Altitude Instructions
  • Flour – increase by 1 tbsp. for extra structure.
  • Eggs – use 1 egg extra egg for added moisture.
  • Oven Temperature – increase to 350° F. 
  • Bake Time – Bake for 8 minutes and keep a close eye on the cookies so they do not burn!
  • Refrigerate the Dough - Refrigerate for 30 minutes or more.
Keyword Birthday, Cookies, Easy Desserts, High Altitude Recipes, Holiday Desserts, Spring Desserts