Christmas Monster Cookies (Naturally Flourless)

Christmas Monster Cookies are chewy, hearty, and loaded with oats, peanut butter, chocolate chips, and festive peanut M&Ms. A hint of warm cinnamon makes them perfectly season-appropriate.

I’m squeezing in one last cookie recipe this year, and it’s a good one. These Christmas Monster Cookies are incredibly simple to whip together and make a big batch, which is exactly what you might need during the holidays. If you’ve made Monster Cookies before, you already know about that chewy oat and peanut butter goodness. These are no different, except for a cozy touch of warm cinnamon and holiday peanut M&Ms to suit the season.

Unlike some monster cookie recipes that use a combination of oats and flour, these Christmas Monster Cookies are completely flourless. That makes them a good option for anyone who’s gluten-intolerant (just be sure to read all ingredient labels). They’re hearty and perfect for cookie swaps, holiday platters, parties – whatever the season has in store for you.

Prep the Oats for Your Christmas Monster Cookies

This recipe starts with lots of oats – 4½ cups of old-fashioned oats, to be exact. Old-fashioned oats give these cookies their signature chewy texture and hearty structure.

In a large bowl, toss the oats together with the baking soda. Baking soda itself is naturally gluten-free, but if you’re baking for someone with high gluten sensitivity, be sure to check the label for added starches or possible cross-contamination.

Make the Monster Cookie Dough

In the bowl of an electric mixer, cream together the peanut butter and softened butter until smooth and well combined. Add the granulated sugar, brown sugar, and cinnamon, then beat again until light and fluffy. Next, add the eggs and vanilla extract, mixing well to fully incorporate. Add the oat mixture and mix just until combined. Finally, stir in the semi-sweet chocolate chips and peanut M&Ms by hand or on the lowest mixer setting. I prefer to do this by hand as the mixer may crack the shells on the peanut candies.

Scoop about 2 tablespoons of dough per cookie and place them on parchment-lined baking sheets, leaving room for spreading. Press a few extra peanut M&Ms onto the tops of the dough balls if desired – this step makes the cookies extra festive and bakery-worthy.

Ingredient Notes and Substitutions

Classic Monster Cookies are made with regular M&M candies (no peanuts), and you can use those in this recipe, if you prefer. The peanut M&Ms make these heartier; a little extra for the holidays.

While peanut M&Ms do not contain gluten ingredients according to the package, they may be produced in facilities that also process wheat. For a certified gluten-free alternative, are a great substitute and offer a similar look and flavor. They are available online and at Whole Foods Market.

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Bake at 350°F

Bake at 350°F for 10–12 minutes, or until the bottoms are lightly golden and the centers still look slightly underdone. That soft center is key to a chewy cookie.

Let the cookies cool on the baking sheets for about 5–7 minutes, until firm enough to move, then transfer to a wire rack to cool completely.

Storing Christmas Monster Cookies

Once completely cooled, store Christmas Monster Cookies in an airtight container at room temperature for up to 5 days. These keep remarkably well, and are suited for travel in care packages.

For longer storage, these cookies freeze beautifully. Place them in a freezer-safe container or zip-top bag for up to 3 months. Thaw at room temperature, or warm briefly in the microwave for that fresh-baked flavor.

Holiday baking doesn’t have to be complicated to be special. These Christmas Monster Cookies come together easily, make plenty, and check all the boxes for a festive, crowd-pleasing treat. I hope they earn a regular spot in your Christmas baking rotation. Enjoy!

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