I love monster cookies, but these Oreo monster cookies might be even better! I stuffed chocolate chip cookie dough with oats, peanut butter, chocolate chips, M&Ms and, of course, crushed Oreo cookies to create these monstrously good cookies. They’re soft, chewy, and so delicious!

I made these Oreo monster cookies with simple ingredients like oats, brown sugar, peanut butter, and vanilla. The dough itself is pretty basic and easy to put together, but the mix-ins are where these monster cookies really shine. The crushed Oreo cookies really add something extra!
What’s in This Oreo Monster Cookie Recipe?
- Flour: Use all-purpose flour for these cookies.
- Leavening: A combination of baking soda and baking powder helps the cookies rise in the oven.
- Brown Sugar: Dark brown sugar adds a rich sweetness that works much better here than granulated white sugar.
- Vanilla Extract: Adds a light flavor to the cookie dough.
- Butter: Use unsalted butter, or omit the extra salt in the recipe if using salted butter. Melt the butter before mixing.
- Eggs: These bind ingredients together to help form the dough.
- Peanut Butter: Use crunchy or creamy peanut butter, whatever you prefer.
- Oats: Be sure to use quick-cooking oats–other types might not fully cook.
- Chocolate Chips: There are lots of other mix-ins in these monster cookies, so I prefer to use mini chocolate chips to make room for everything.
- M&Ms: These color-coated chocolate candies add color and texture. If you prefer, place them in a resealable bag and crush them up before mixing in.
- Oreo Cookies: Crush Oreo cookies into bite-sized pieces before folding them into the monster cookie dough.
Note: This recipe is one of those few exceptions on our site that has more than 10 ingredients. We try to keep things VERY easy around here, and limiting ingredients and time spent is one of our favorite ways. That being said, this recipe is too delicious to leave out of our recipe box! It’s an exception that is so flavorful and worth the extra ingredients if you have the time and resources to make it.
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How to Store
Let Oreo monster cookies fully cool after baking, then place them in an airtight container or resealable bag. Store them at room temperature for 3 days in the refrigerator for 5 days, or in the freezer for up to 1 month. Let them thaw at room temperature or in the fridge before serving.
Tips for Success
- You can chill cookie dough for 1-2 days in the refrigerator if this is something you want to make ahead of time. Just remember to pull it from the refrigerator to soften for about 15-20 minutes before getting ready to bake.
- If you’d like, after placing the cookie dough balls on the baking sheet, you can place a few additional M&M’s and Oreo pieces right on top of each ball to make them look extra pretty when they come out of the oven!
- If you’re making these for Halloween, add some candy eyes on top for a spooky (but cute) twist.
Oreo Monster Cookies Recipe
Ingredients
- 1½ cups all-purpose flour
- 1 teaspoon baking soda
- 1½ cups dark brown sugar
- 1 teaspoon baking powder
- 1 teaspoon kosher salt
- 1 tablespoon pure vanilla extract
- 1 cup unsalted butter melted (2 sticks)
- 2 large eggs
- ½ cup creamy peanut butter
- 2 cups quick-cooking oats
- ½ cup mini chocolate chips
- 1 cup M&M’S
- 1 cup crushed Oreos (from about 12 cookies)
Equipment
- Kitchen Scale (optional)
- Hand Mixer
- Baking Sheet
Instructions
- In a large bowl, combine the flour, baking soda, brown sugar, baking powder, and salt. Set aside.1½ cups all-purpose flour, 1 teaspoon baking soda, 1½ cups dark brown sugar, 1 teaspoon baking powder, 1 teaspoon kosher salt
- Add the vanilla extract, melted butter, eggs, and peanut butter. Using a hand mixer, blend everything together well.1 tablespoon pure vanilla extract, 1 cup unsalted butter, 2 large eggs, ½ cup creamy peanut butter
- Slowly add in the oats, 1 cup at a time.2 cups quick-cooking oats
- Use a rubber spatula to gently fold in the chocolate chips, M&M's, and Oreos.½ cup mini chocolate chips, 1 cup M&M’S, 1 cup crushed Oreos
- Cover bowl and place in the refrigerator for 15-20 minutes.
- Preheat oven to 350°F. Line a baking sheet with parchment paper.
- Scoop 2-tablespoon-sized balls of dough and place them 2 inches apart on the prepared baking sheet.
- Bake for 8 minutes, then rotate the pan around and bake for an additional 5-8 minutes. Cookies are ready when an inserted toothpick comes out clean! Cookies should be brown but not too dark. You don’t want to overcook them, they should still be soft inside!
- Let cookies cool for a few moments on pan before transferring them to a cooling rack.
Notes
How to Make Oreo Monster Cookies Step-by-Step
Mix the Dry Ingredients: In a large bowl, combine 1½ cups of all-purpose flour, 1 teaspoon of baking soda, 1½ cups dark brown sugar, 1 teaspoon of baking powder, and 1 teaspoon of kosher salt. Set aside.
Add the Wet Ingredients: Add 1 tablespoon of vanilla extract, 1 cup of melted unsalted butter, 2 large eggs, and ½ cup of peanut butter. Using a hand mixer, blend everything together well. Slowly add in 2 cups of quick-cooking oats, 1 cup at a time.
Fold the Mix-Ins: Use a rubber spatula to gently fold in ½ cup of mini chocolate chips, 1 cup of M&M’s, and 1 cup of crushed Oreos.
Chill the Dough: Cover the bowl and place it in the refrigerator for 15-20 minutes.
Scoop the Cookies: Preheat the oven to 350°F. Line a baking sheet with parchment paper. Scoop 2 tablespoon-sized balls of dough and place them 2 inches apart on the prepared baking sheet.
Bake the Cookies: Bake for 8 minutes, then rotate the pan around and bake for an additional 5-8 minutes. Cookies are ready when an inserted toothpick comes out clean! Cookies should be brown but not too dark. You don’t want to overcook them, they should still be soft inside! Let cookies cool for a few moments on pan before transferring them to a cooling rack.
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