How to Make Monster Cookies

Our ultra soft and chewy monster cookie recipe is packed with peanut butter, oats, chocolate candies, and chocolate chips. Quick and easy to make, and easy to customize, this flourless cookie recipe is sure to be a hit with your family and friends!

Baking cookies is my absolute favorite way to spend time in the kitchen, and this monster cookie recipe holds a special place in my heart. About a decade ago, my friend Liz brought these incredible monster cookies to share at a winter cabin weekend with friends. They were hands down the best monster cookies I’d ever tasted… perfectly chewy, loaded with peanut butter and chocolate, and naturally gluten free since Liz has celiac disease. We all exchanged recipes after that weekend, and for years, whenever I wanted to make them, I’d just click the link to her recipe. Until one day, the link was gone and the recipe had disappeared from the internet.

As someone who’s developed nearly 70 dessert recipes for this website, including over 20 cookie recipes, and has been baking for 30+ years, I wasn’t about to let my favorite monster cookie become a lost memory. I set out to recreate the cookie I loved so much, testing batch after batch to get the ratios just right. I tried versions with flour, thinking it might improve the texture, but honestly, they just weren’t as good as the flourless version. The oats alone create the perfect chewy texture without any flour needed. After extensive testing, trying various amounts of chocolate chips and M&Ms, and tweaking the sugar ratios, I finally achieved a recipe I felt confident was on par with (or maybe even better than?) the cookie I remembered. Now I make these all the time, and they always bring me back to that cozy cabin weekend.

Monster Cookies Recipe Ingredients

• Salted butter. Butter adds richness, tenderness, moisture, and structure to our cookies, which is especially helpful in this flourless cookie recipe.
• Granulated Sugar AND Brown Sugar. We’re using a combination of both white sugar and brown sugar to create cookies with the perfect level of sweetness, moistness, and chewiness.
• Large eggs. Using whole eggs (versus using just an egg yolk or an egg white) helps provide structure, leavening, and moisture.
• Vanilla Extract. Adds depth of flavor in our cookie recipe.
• Creamy peanut butter. In addition to adding a nutty flavor, peanut butter contributes this cookie’s soft consistency and can contribute to a more delicate and crumbly texture too. While I love natural peanut butter, I’ve found it can be challenging to bake with. I tend to use JIF when baking because of having consistently good results with it.
• Salt. A little is used to help enhance the other flavors.
• Baking soda. Used as the leavening agent in our cookies, baking soda contributes to the wonderfully chewy texture in this recipe.
• Old-fashioned rolled oats. Oats add flavor, texture, and chewiness to our cookies. Old fashioned oats (also called rolled oats) will give the very best texture to your cookies, but in a pinch quick-cooking oats (NOT instant oats) will work for your cookies as well. You can learn more about the different types of oats and how to use them in this detailed informational post about oats.
• Semi-sweet chocolate chips AND milk chocolate m&ms. We’re mixing in both chocolate chips and m&ms for the ultimate monster cookie experience.

See the recipe card at the bottom of the post for ingredient measurements and full directions.

How to Make Our Recipe For Monster Cookies

Preheat your oven to 350°F. Set out your baking sheets, optionally lining with parchment paper if desired.

Add the the butter, white sugar, and brown sugar to the bowl of a stand mixer with a paddle attachment (or into a large mixing bowl.

Cream the butter and sugars together with low to medium speed (or using a wooden spoon if mixing by hand) until the mixture is lighter and fluffy (it will still look a little grainy).

Add in the eggs and stir to combine into the butter and sugar mixture.

Next, stir in the vanilla extract and peanut butter until well combined.

Add the salt, baking soda, and rolled oats to the mixture and stir to combine.

Gently mix in the chocolate chips and m&ms until well dispersed through the dough.

Using a medium cookie scoop (equal to about 2 Tablespoons worth of dough), scoop dough balls onto the cookie sheets, keeping them about 2 inches apart.

Optionally, press and additional 3-5 m&ms and/or chocolate chips on top of each dough balls.

Bake for 9-12 minutes until the edges look set and the cookies look golden brown.

Remove them from the oven and allow to set on the cookie sheet for a few minutes. Then transfer to a wire cooling rack to cool completely.

Best Monster Cookie Recipe Variations

Make them festive with seasonal m&ms! Halloween monster cookies, Christmas monster cookies, Valentines monster cookies, Easter monster cookies, 4th of July monster cookies… you can do them all!

Change your mix-ins. My go to is half m&ms and half chocolate chips for a total of 1 Cup of mix-ins for a single batch as noted in the recipe card, but this is where you can have fun! You can try some chopped nuts like pecans or walnuts, shredded coconut, mini Reese’s, raisins, etc.

This recipe is vegetarian and gluten-free as written. If serving to someone with celiac just be sure to confirm the oats you’re using are certified to be gluten-free, and while most semi-sweet chocolate chips are gluten free you can also purchase a chocolate chip brand (like Enjoy Life chocolate chips) that is certified to be gluten free if you’re concerned.

Monster Cookie Tips For Perfection

Use a cookie scoop for perfectly sized cookies. A medium cookie scoop ensures all your cookies are the same size, which means they’ll bake evenly and be done at the same time. It also makes portioning the dough super quick and easy too. If you don’t have a cookie scoop, you can use a spoon to measure out about 2 tablespoons of dough per cookie, but a scoop makes the process much easier and more consistent.

Don’t overbake them. For the ultimate soft and chewy texture, pull your cookies from the oven when the edges look just set and golden brown but the centers still look slightly underdone. They’ll continue to bake on the hot pan as they cool. Overbaked cookies will be dry and crunchy rather than soft and chewy.

Let them cool on the baking sheet first. Allow your cookies to rest on the baking sheet for a few minutes after removing from the oven before transferring to a cooling rack. This helps them set up properly and prevents them from breaking apart when you move them.

Use JIF or another standard peanut butter. While natural peanut butter is great for eating, it can be tricky to bake with because of the oil separation. I’ve found that JIF (or similar standard creamy peanut butters) gives the most consistent results in this recipe.

Press extra candies on top before baking. Adding a few extra m&ms or chocolate chips on top of each dough ball before baking makes your cookies look pretty and ensures every bite has plenty of chocolate.

Monster Cookie Storage

Store fully cooled cookies in an airtight container at room temperature for up to 5 days (if they last that long!).

Freezing Before or After Baking

To freeze before baking: Make the cookie dough as directed in the recipe card. Line a baking sheet with waxed paper, and like you would before baking, scoop dough into balls. Place dough balls onto the lined baking sheet, without them touching, and chill the pan in the freezer for 1 hour (this is called “flash freezing”). Once the cookie dough balls are cold and solid, place them into a large freezer bag.

When ready to enjoy, you can bake the frozen cookie dough balls directly from frozen! Place them onto a baking sheet as noted in the recipe card, and simply add an extra 2-3 minutes to the bake time.

I personally love this option and because having a freezer stash of cookie dough balls to bake later is THE BEST. That way you can have freshly baked cookies any time, and you can also bake off a smaller amount of cookies if you want!

To freeze baked cookies: Place fully cooled cookies into a freezer bag or air-tight container and store in the freezer for up to 3 months. When ready to enjoy, remove the cookies from the freezer and allow them to thaw overnight in the refrigerator.