These monster cookies are the best sweet treat! You'll love the chewy peanut butter oatmeal cookies with M&Ms and chocolate chips. This recipe is easy to make, too.
If you are looking for a deliciously chewy peanut butter oatmeal cookie loaded with sweet add-ins, this monster cookie recipe is for you!
With the perfect combination of sweet and salty flavors, they will satisfy even the biggest sweet tooth.
Why You'll Love This Recipe
- Calls for basic ingredients. If you enjoy baking desserts, you may already have most of these ingredients in your kitchen.
- A no-chill dough. A lot of cookie recipes tell you to chill the dough before baking. Although it does help prevent spreading, it isn't necessary for this recipe!
- Freezer friendly. Save time by freezing a double (or triple!) batch of cookie dough. The baked cookies freeze well for up to 3 months, too!
Ingredients
See ingredient substitutions in the next section. ⬇️
To make this monster cookie recipe, you'll need:
- creamy peanut butter: To prevent greasy cookies, use a no-stir variety.
- unsalted butter: If you can afford it, I recommend using European butter rather than American-made. The extra butterfat content adds more flavor.
- white granulated sugar
- light brown sugar
- large eggs
- vanilla extract
- old fashioned rolled oats: Do not use quick-cooking oats or instant oatmeal.
- all-purpose flour
- salt: It's important to use kosher or sea salt, not iodized table salt.
- baking soda: If you haven't used it in a while, test your leavener for freshness. This is because out of date leaveners won't produce the gas bubbles needed for the cookies to rise in the oven.
- semi-sweet chocolate chips
- M&Ms
Substitutions and Recipe Variations
- peanut butter: For more texture, use crunchy peanut butter. You can use any nut butter as a substitute, but it will affect the flavor of the cookies.
- unsalted butter: If all you have is salted butter, that's fine! Just omit the salt this recipe calls for.
- eggs: I haven't tested this recipe with any egg substitutes, but If you want to try, feel free! For tips and suggestions, read my article on Egg Substitutions for Baking.
- white granulated sugar: To cut down on the calories of your peanut butter cup cookies, feel free to use any cup-for-cup granulated sugar substitute. Monk fruit sugar is a good option.
- light brown sugar: Dark brown sugar works too, but it will add a stronger molasses flavor.
- vanilla extract: If you need an alcohol-free substitute, use vanilla essence. Any other flavor of extract can be substituted for vanilla. If necessary, you can even omit this ingredient without it affecting the flavor of your cookies too much.
- all-purpose flour: To make gluten free monster cookies, substitute the AP flour with any cup-for-cup variety of gluten free all-purpose flour. Popular brands are made by Bob's Red Mill and King Arthur Flour.
- baking soda: Do not use baking powder. Although they're both leaveners, there are specific differences between baking soda and powder.
Making Peanut Butter Oatmeal Monster Cookies
Summary only. The complete recipe instructions are in the card at the bottom of this post ⬇️
- Cream together the butter, peanut butter, and sugars.
- Incorporate the remaining wet ingredients, then the dry ingredients.
- Arrange scoops of cookie dough 2 inches apart on a parchment lined baking sheet.
- Bake for 12-15 minutes. After removing them from the oven, let the cookies sit on the baking pan for 5 minutes.
Liz's Tips for the Best Cookies
- For a softer texture, substitute half of the old fashioned rolled oats with quick-cooking oats.
- To avoid getting shells in the dough, crack the eggs in a separate bowl before adding them to the other ingredients.
- To prevent the cookies from spreading in the oven, consider refrigerating the dough for at least 30 minutes before baking. Chilling is optional, but it does help ensure thick and chewy cookies.
- For even baking, keep the balls of cookie dough the same size. Either use a cookie scoop for portioning the dough, or weigh the balls on a food scale.
- Keep the baked cookies on the pan for 5 minutes before transferring them to a cooling rack. Peanut butter oatmeal cookies are notorious for falling apart while they're warm.
Storing and Freezing Instructions
Storing: Keep the cookies for up to 5 days in an airtight container at room temperature.
Freezing: You can freeze the baked cookies for up to 3 months in an airtight container. Thaw completely before enjoying, or warm them up in a microwave for 10-20 seconds.
Freezing Unbaked Cookie Dough
You can freeze the dough for up to 3 months. Before freezing, scoop and place balls of cookie dough on a parchment lined baking sheet, or use these cookie dough freezing trays. Once the dough freezes, transfer the balls to an airtight, freezer-safe container.
When you're ready to bake:
- Remove the cookie dough from the freezer.
- Arrange unbaked cookies 2 inches apart on a baking sheet lined with parchment paper.
- Thaw at room temperature for 30 minutes before baking.
Check out my post, How to Freeze Cookie Dough, for helpful tips.
FAQs
Why are my cookies falling apart?
If you don't allow peanut butter oatmeal cookies to cool on the baking sheet before moving them, they tend to fall apart.
Why are the cookies so flat?
Your oven may be too hot, which can cause the dough to spread too much. Next time, chill your dough for 30 minutes or so before baking.
Does refrigerating cookie dough make a difference?
Yes, if you refrigerate the cookie dough, it can help prevent the cookies from spreading during baking. The cold dough is stiffer, so it won't spread before it starts to bake.
Peanut Butter Oatmeal Monster Cookies
Enjoy chewy, delicious peanut butter oatmeal cookies packed with chocolate and M&Ms. This monster cookies recipe is the perfect sweet treat!
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Servings: 36 cookies
Calories: 141kcal
Ingredients
- ½ cup creamy peanut butter use a no-stir variety
- ¾ cup unsalted butter at room temperature (1 and ½ sticks)
- ½ cup granulated white sugar
- ½ cup light brown sugar
- 1 large egg
- ½ tablespoon vanilla extract
- ¾ cups all-purpose flour
- ½ teaspoon baking soda
- ¼ teaspoon sea salt omit if using salted butter
- 1 cup old fashioned rolled oats
- ¾ cup M&Ms
- ¾ cup semi-sweet chocolate chips
Instructions
- Preheat oven to 350°F, and line two baking sheets with parchment paper. Set aside.
- On medium-high speed in a stand mixer fitted with the paddle attachment, or using an electric hand mixer and large mixing bowl, cream the peanut butter, butter, and both sugars together for 1-2 minutes, until light and fluffy.
- Add the egg and vanilla extract; continue mixing on medium speed until well combined.
- In a separate bowl, whisk together the flour, baking soda, and salt.
- Reduce the mixer speed to low. Gradually add the dry ingredients to the wet mixture, mixing until just combined. *Avoid over mixing, which can cause cookies to be dry and crumbly.
- Using a mixing spatula or spoon, gently fold in in the rolled oats, M&M's and chocolate chips, evenly distributing them throughout the dough.
- Use a medium-sized cookie scoop or table spoon to portion the dough into 2-inch balls (about the size of a golf ball). Arrange them about 2 inches apart on the prepared baking sheets.
- Press down lightly on each cookie dough ball to flatten them slightly.
- Bake in preheated oven for 12-15 minutes, or until the edges are light golden brown and the centers are just barely set.
- Remove from the oven and let the monster cookies cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.
Helpful Notes and Tips From Liz
- For a softer texture, substitute half of the old fashioned rolled oats with quick-cooking oats.
- To prevent cookies from spreading in the oven, consider refrigerating the dough for at least 30 minutes before baking. Chilling is optional, but it helps ensure thick and chewy cookies.
- For even baking, make balls of cookie dough the same size. Either use a cookie scoop for portioning the dough, or weigh them on a food scale.
- Remove the cookie dough from the freezer.
- Arrange unbaked cookies 2 inches apart on a baking sheet lined with parchment paper.
- Thaw at room temperature for 30 minutes before baking.
Nutrition
Serving: 1cookie | Calories: 141kcal | Carbohydrates: 15g | Protein: 2g | Fat: 8g | Saturated Fat: 4g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 0.2g | Cholesterol: 16mg | Sodium: 52mg | Potassium: 58mg | Fiber: 1g | Sugar: 10g | Vitamin A: 137IU | Vitamin C: 0.03mg | Calcium: 15mg | Iron: 1mg
Molly Moore
WOW! Probably one of the best cookies I’ve ever had!! Followed the recipe exactly and they came out perfect; 12 min and 5 resting on the pan. These will now be my go-to cookie recipe!! Awesome work again, Liz!