Monster Peanut Butter-Oatmeal-Chocolate Chip Cookies

Monster Cookies Recipe

This cookie is the Frankenstein’s monster of the cookie world. One part oatmeal cookie, one part peanut butter cookie, and one part chocolate chip cookie, it’s many things to many people. We re-created this rather large, chewy cookie as an homage to the Monster Cookies we remember eating in grade school, only our version is slightly less sweet and a whole lot better.–Matt Lewis and Renato Poliafito

LC Monster Mash Note

This recipe creates a mash up of sorts from quite a lot of various ingredients that may, at first blush, collectively seem quite monstrous. Yet what results is not to be missed by anyone who feels their soul’s deepest desire can be found in chewy, substantial cookie goodness.

Monster Peanut Butter-Oatmeal-Chocolate Chip Cookie Recipe

  • Quick Glance
  • 20 M
  • 50 M
  • Makes 36 cookies


  • 1/2 cup all-purpose flour
  • 1 tablespoon baking soda
  • Pinch of salt
  • 5 3/4 cups rolled oats
  • 3/4 cup cold unsalted butter, cut into cubes
  • 1 1/2 cups firmly packed light brown sugar
  • 1 1/2 cups granulated sugar
  • 5 large eggs
  • 1/4 teaspoon vanilla extract
  • 2 cups creamy peanut butter
  • 6 ounces bittersweet chocolate, cut into chunks
  • 1 cup (6 ounces) M&M’s (regular or peanut)


  • 1. In a large bowl, whisk together the flour, baking soda, and salt. Add the oats and stir until the ingredients are evenly combined.
  • 2. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter until smooth and pale in color. Add the sugars and mix on low speed until just incorporated. Do not overmix.
  • 3. Scrape down the bowl and add the eggs, 1 at a time, scraping down the bowl and beating until smooth after each addition, about 20 seconds. Add the vanilla and beat until just incorporated.
  • 4. Scrape down the bowl and add the peanut butter. Mix on low speed until just combined. Add the oat mixture in 3 additions, mixing on low speed until just incorporated.
  • 5. Use a spatula or wooden spoon to fold in the chocolate chunks and M&Ms. Cover the bowl tightly and refrigerate for 5 hours.
  • 6. Preheat the oven to 375°F (190°C). Line 2 baking sheets with parchment paper.
  • 7. Use an ice cream scoop to plop the dough in 2-tablespoon-size balls onto the prepared baking sheets, spacing them about 2 inches apart. Bake for 12 to 15 minutes, switching and reversing the sheets halfway through the baking time, until the cookies just begin to brown. Let the cookies cool on the pans for 8 to 10 minutes before transferring them to a wire rack to cool completely. The cookies can be stored in an airtight container for up to 3 days.
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Recipe Testers Reviews

I’ve seen a lot of oatmeal cookie recipes, and a lot of peanut butter recipes, but not many that combine the two. I used my large scoop as instructed, but I ended up with more than 36 cookies. The other odd thing is that the color of the M&M’s started bleeding as time went on, so my last two to three batches had some faded M&M’s. It’s as if the liquid of the dough wore through the color on the candy coating. This is more of an aesthetic than taste-based problem. The overall taste of these cookies was good. I’ve always liked the combination of chocolate and peanut butter.

This recipe surprised us in many ways. First, we were surprised to see how smoothly the butter creamed while cold. The amount of flour called for was minimal, but the dough was very stiff due to the amount of peanut butter and oats. We didn’t have regular-sized chocolate chips, so we used the mini semisweet chips. The recipe was easy to mix together, but the cookies took a very long time to bake— because of their size, you could only fit four on a cookie sheet at a time. Luckily, we read through the recipe first, but notes on prep and cook time would have been helpful. It’s an all-day experience to make these cookies due to the 5-hour chill time, then more than 1 1/2 hours of total baking time. Using the regular ice cream scoop gave me the exact yield stated in the recipe. I would recommend a strong, high-quality ice cream scoop, because the dough is so thick, it will break a weaker scoop (don’t ask).

The recipe doesn’t state to flatten the cookies, but this is a crucial step. The first batch baked as stated gave us little igloo-shaped cookies that were raw in the middle. After those, we flattened the dough, and they all baked in 12 minutes. If you want a soft cookie, 12 minutes is good, and if you like a crunchier cookie, bake for 14 minutes. The baking time should also be adjusted as the dough softens.

The raw dough had a strong peanut butter flavor, so we were concerned it would overpower the cookies—but the finished product provided a nice balance between peanut butter and chocolate. The end result is a great-tasting cookie. These cookies are hand-size, and we’re not talking about palms—this includes fingers, too. I can only eat half of a cookie at a time, but the grandkids didn’t have any problems finishing them whole. Making these is a great way to get kids in the kitchen and cooking.

I had initial concerns that these cookies would be too schizophrenic for me, but I was delightfully surprised with the results. I like that the oats made for a less dense peanut butter cookie, and I can’t think of a situation where adding chocolate chips didn’t improve a dessert. These cookies are chewy, and continued to stay soft even a day or two after baking. This recipe does call for a large quantity of several ingredients: peanut butter and oats, most notably. Prepare to delay your gratification, since the dough needs to chill for 5 hours. Were the M&M’s essential to the recipe? Probably not. I wouldn’t worry if you don’t have M&M’s on-hand and you’d like to try this recipe.

If you love oatmeal, peanut butter, and chocolate, these cookies are the bomb! This is the best new recipe for cookies that I’ve come across in a long time—and I try lots of cookie recipes. I refer to them as “healthy” cookies because of the quantity of oatmeal they contain. I substituted Reese’s Pieces for the M&M’s, which gave the cookies a more pronounced peanut butter taste, and they were great. Everyone at my workplace loved them. Next time, I’d store them in a tin to try to keep them crisp. I had only covered them, and they softened overnight.

These cookies were fabulous. Everyone who tried them gobbled them up right away, with no complaints. What I especially liked about them is that they weren’t overly sweet—they weren’t very sweet at all, actually. I was skeptical to make the dough with cold butter (rather than room-temperature butter), but it worked very well. The small amount of flour also made me skeptical, but the dough was the perfect consistency. I liked that they baked into chewy cookies with soft centers; it’s the perfect texture for the medley of peanut butter, oatmeal, and chocolate. I baked some of the cookies after the 5-hour refrigeration, and I baked some after overnight refrigeration. Both batches were perfect. Also, I divided the dough in two. One had the semisweet chips and M&M’s, as called for; the other had semisweet chips and milk chocolate chips. Both types were a hit.


  1. I’ve made this recipe from Baked a few times and adore these cookies! I love the incredible amount of oats in the cookies and the overall chewy, soft texture and peanut butter-chocolate combination. Everyone I’ve shared them with adored these cookies.

    1. Aren’t they great Monica, so many great things packed into one cookie, it’s hard not to like them.

  2. Our cookies turned out really flat :( The dough looked almost melted on the cookie sheets. We followed all the directions and that was even the first batch on cool cookie sheets. We used our KitchenAid mixer on low to combine the ingredients. The only thing I can think of did we over mix the dough? We were really careful not to mix it too long though. We were just disappointed they didn’t turn out like everyone else’s has seemed to and they sounded so good.

    1. Hi Ashley, I’m so sorry these cookies didn’t turn out well for you. I’ve made them many times, and I’ve never had the flat-cookie problem.

      A few questions: 1. Did you use straight-from-the-fridge butter? 2. Did you use all-purpose flour? 3. Did you use natural or regular peanut butter, such as Skippy or Jif?

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