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Peanut Butter Oatmeal Monster cookies are loaded with creamy peanut butter, oats, chocolate chips and m&m candies. They bake up super thick, with chewy edges and incredibly soft centers.
Monster Cookies Recipe
If there’s one recipe you should make for halloween, it’s monster cookies! Nothing spooky or scary about this chewy monster cookie recipe… except for the fact that they’re scary delicious. But they’re fun to make, and give off halloween vibes with their name and abundance of chocolate chips and colorful M&M chocolate candy.
I make these every halloween for our neighborhood party and they literally fly off the tray! The only other dessert that competes with them is my candy corn blondies!
What are Monster Cookies?
The web is home to many monster cookie recipes, and they vary greatly. Some are basically just regular cookies with m&m’s and chocolate chips. Others have oats, nuts, butterscotch chips, or coconut. And then there are the ones that incorporate PEANUT BUTTER.
My chewy monster cookie recipe is a combination all the above! Loaded with oats, peanut butter, M&M chocolate candy, cinnamon, vanilla, and of course, chocolate chips! I also use a combination of brown sugar and granulated sugar, which adds depth of flavor. They’re thick, chewy, and so delicious.
Ingredients for Monster Cookies
- Butter: Bring butter to room temperature before baking! Butter that is cold won’t properly cream.
- Peanut Butter: Creamy peanut butter is king when it comes to these cookies! JIF, Skippy, and Peter Pan brand are favorites and work great in this recipe! Don’t use chunky peanut butter, natural peanut butter, almond butter, or other nut butters.
- Vanilla Extract: Adds rich flavor while enhancing the other flavors in these chewy monster cookies.
- Sugar: A combination of granulated sugar and brown sugar sweeten the cookies and add incredible depth of flavor. Do not reduce the amount of sugar.
- Eggs: You’ll use whole eggs and an egg yolk in this recipe. Use large eggs and bring them to room temperature before baking.
- Flour: Measure with a digital kitchen scale or lightly spoon it into the measuring cup. Never pack flour, this leads to dry cookies that don’t spread.
- Oats: The combination of old-fashioned oats and quick oats give this cookie recipe incredible texture.
- Baking Soda: This chemical agent helps the cookies spread in the oven.
- Baking Powder: This is my secret ingredient to thick and puffy cookies!
- Cinnamon: Adds depth of flavor and warmth to the cookie dough.
- Salt: Balances the overall sweetness and helps enhance the flavors in the recipe. Try adding a sprinkle of flaky sea salt on top for an extra delicious treat!
- M&M Candies: Use plain M&M chocolate candy for a classic monster cookies. Or use seasonal ones like red & green to celebrate Christmas or white and pink to celebrate Valentine’s Day!
- Semi-Sweet Chocolate Chips: Ue dark chocolate chips, white chocolate chips, or butterscotch chips instead. Or use a combination of all the above!
- Salted Peanuts: These nuts add delicious crunch and enhance the overall peanut butter flavor. Feel free to omit – or use pecans or walnuts.
How to Make Monster Cookies
- Cookie Dough: You’ll need a stand mixer or electric hand mixer to properly cream the butter and sugars. Once you combine the dry ingredients with the wet ingredients, mix gently. Over mixing causes dry cookies.
- Chill: Cover the bowl and place it in the fridge for 30 minutes, or up to 2 days. If you chill longer than 2 hours, let the dough sit at room temperature for 15 minutes before scooping.
- Cookie Prep: Preheat the oven and line two large baking sheets with parchment paper 30 minutes before baking.
- Scoop: Scoop dough onto the prepared cookie sheet. Gently press each cookie ball, slightly flattening it. Sprinkle the tops with some extra oats, if desired.
- Bake: For about 10 to 12 minutes. The exact baking time will vary depending on your baking sheet and oven.
- Cool: On the baking sheet for 10 minutes, then transfer the cookies to a cooling rack and cool completely.
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Why Didn’t My Monster Cookies Spread?
- Too much flour: This is the number one culprit for dry and puffy cookies that don’t spread. Measure flour properly by using a digital kitchen scale. Or, fluff the flour in the bag and lightly spoon the flour into the measuring cup. Fill until it overflows, then scrape the top smooth with a knife.
- Too many Oats: Similar to flour, oats absorb liquid ingredients. If you add more oats than the recipe calls for, your cookies will turn out dry.
- Butter is too Cold: For butter to properly cream, it needs to be at room temperature. Cold butter won’t break or bond properly with the other ingredients.
- Wrong Peanut Butter: Not all peanut butter is created equal. Use traditional creamy peanut butter, like JIF or Skippy.
- Other Change in The Recipe: Forget to add the egg yolk? Use small eggs instead of large? Use gluten free flour? Or all quick oats instead of a mix?
Tools for this Monster Cookie Recipe
Large Baking Sheets: Light colored cookies sheets work best for baking cookies. They help reduce over browning in the oven. A dark cookie sheet will work, but may yield darker cookies.
Electric Hand Mixer or Stand Mixer: You need one of these options to make the cookie dough.
Large Mixing Bowl: If you’re using a hand mixer, you’ll need a large bowl to make the cookie dough.
Cookie Dough Scoop: A large and sturdy cookie scoop is a cookie baking must-have!
Parchment Paper: A must-have for lining your cookies sheets. Do not sub wax paper or aluminum foil.
Soft Batch Peanut Butter Monster Cookies
Ingredients
- 1 cup (227g) unsalted butter room temperature
- 1 cup creamy peanut butter room temperature
- 2 teaspoons pure vanilla extract
- 1 and 1/4 cups (269g) light brown sugar, packed
- 1/3 cup (66g) granulated sugar
- 2 large eggs room temperature
- 1 large egg yolk room temperature
- 1 and 3/4 cups (210 grams) all-purpose flour
- 3/4 cup old-fashioned oats
- 1/2 cup quick oats
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- 1/2 teaspoon ground cinnamon
- 1/2 teaspoon salt
- 1 and 1/2 cups M&M candies
- 1 and 1/2 cups semi-sweet chocolate chips
- 1/2 cup salted peanuts roughly chopped
Instructions
- In the bowl of a stand mixer fitted with the paddle attachment or in a large bowl using a handheld electric mixer, beat the butter on medium speed until smooth and creamy.
- Add in the peanut butter and vanilla and beat until smooth, about 2 minutes.
- Next add in both sugars and beat until light and fluffy, scraping down the sides and bottom of the bowl as needed, about 2 minutes.
- Add in the eggs and yolk, one at a time, beating well after each addition. Turn mixer off.
- Add in the flour, oats, baking soda, baking powder, cinnamon, and salt. Whisk the ingredients together lightly before turning the mixer back on low and mixing in the dry ingredients until just combined. Be sure not to over mix here.
- Turn mixer off and use a spatula to fold in the M&Ms, chocolate chips, and peanuts.
- Cover the bowl and place it in the fridge for 30 minutes, or up to 2 days.
When ready to bake:
- Preheat oven to 350 degrees (F). Line two large baking sheets with parchment paper.
- Scoop two tablespoon sized mounds of dough onto the prepared cookie sheet, leaving a few inches between each cookies for spreading. Gently press down on each cookie ball, slightly flattening the ball. This will help them spread evenly in the oven. Sprinkle the top of each cookie with some extra oats, if desired.
- Bake one tray at a time, for 12 minutes, or until the edges are golden and the centers have set. If any edges spread out while baking, use a spatula and gently press them back in as soon as you remove the cookies from the oven.
- Cool cookies on the baking sheet for 10 minutes before transferring them to a cooling rack.
My kids loved helping me make and eat these! A new fall tradition!
I made these for my parents and coworkers last year, and I’ve been receiving endless requests to bake these again! Absolutely wonderful texture and flavour, a perfect mix of sweetness, chocolate, saltiness and heartiness from the oats! I used dairy-free butter that I browned and allowed to cool for an extra note of nuttiness and for additional depth in flavour.
I was curious about baking time and/or baking temperature if I were to try to turn these cookies into cookie bars for easier sharing—what updates in regard to temperature or time would you advise?