Monster Cookies

The ultimate treat packed with chocolate chips, peanut butter, and colorful M&M’s, this monster cookie recipe is a true crowd-pleaser! Whether you’re a cookie lover or a fan of all things sweet, get ready to sink your teeth into the perfect blend of chewy, crispy, and loaded with flavor.

For more sweet treats, try my recipes for S’mores cookies, cheesecake brownies, kiss cookies, and soft sugar cookies.

Delicious monster cookies on a white plate, just waiting to be eaten.

Recipe Science

Combining oats and flour creates a chewy texture by absorbing moisture while maintaining structure and softness.
Using a mix of peanut butter and butter adds fat, contributing to the rich flavor and helping bind the ingredients for a tender crumb.
Baking the cookies allows the sugars to caramelize through the Maillard reaction, enhancing the depth of flavor while providing a slightly crisp exterior.

Why It Works

If you’re looking for the ultimate cookie experience, this recipe is for you! The dough has a little of everything: creamy peanut butter, chewy oats, M&Ms, and chocolate chips. It’s a sweet indulgence that any cookie monster would love!

The base is the ideal ratio of ingredients to balance the sweet and savory flavors. Chilling the dough is not necessary; just scoop it onto the tray and pop it in the oven. When baked, the cookies yield delicious crisp edges and chewy centers.

Ingredients You’ll Need

Ingredients needed to make this monster cookie recipe.

Oats: Thick old-fashioned oats add a chewy texture and prevent the dough from spreading too much as it bakes.
Flour: Use all-purpose flour; it contains a moderate 10 to 13% protein level. This adds structure while keeping the texture tender in the center.
Sugar: Use two types of sugar: granulated and brown sugar. The crystallized sugar creates crisp edges. The dark brown sugar adds a molasses taste, and it’s a humectant that keeps the centers soft.
Peanut Butter: Use my homemade peanut butter or smooth and creamy Jif or Skippy. They won’t separate in the dough, and it’s easier to incorporate. Add chopped peanuts for extra crunch.
Chocolate: A mix of semi-sweet chocolate chips and colorful M&M candies with crisp candy coating make for an interesting taste and texture.
Leavening Agents: Baking soda helps puff up the middle so it’s not so dense. It also helps with slight spread and crispiness. Eggs help with binding and aeration.
Flavoring: Vanilla extract enhances the baked notes. A small amount of salt balances the sweetness of the sugars and chocolate.

See the recipe card below for all ingredients and measurements (US and metric).

Ingredient Substitutions

Now that you know how to make monster cookies, try these tasty variations:

Chocolate: Try using different types of chocolate, like milk chocolate, dark chocolate, or white chocolate chips. There are even butterscotch, caramel, or peppermint chips. For different holidays, you can switch up the color of the M&M candies.
Nut Butter: Change up the peanut butter flavor with almond butter, cashew butter, or sunflower butter if you have a nut allergy.
Nuts: Add extra crunch with chopped peanuts, peanuts, or almonds.
Flavoring: Instead of vanilla, try almond extract, peppermint, or mint. Experiment with warm spices like cinnamon, nutmeg, ginger, and allspice, or add pumpkin pie spice. Add toffee bits or crushed candy canes.
Fruit: Add dried fruits like raisins, cranberries, or currants.

How to Make Monster Cookies

Step 1: Preheat the Oven

Preheat the oven to 350ºF (177ºC) while preparing the cookie dough. Set the oven rack to the middle position.

Bowl of oats and flour that has been whisked together.

Step 2: Prepare the Dry Ingredients

With the varying sizes of the dry ingredients, it’s essential to give them a good mix. Whisk the oats, flour, baking soda, and salt to disperse the fine particles. This is especially important for the leavening agent so that each cookie rises properly during baking.

Softened butter, peanut butter and brown sugar in the bowl of a stand mixer.

Step 3: Mix the Butter and Sugars

Before mixing, soften the butter to about 65ºF (18ºC), just below room temperature. I use the beater attachment to cream the butter, sugar, and peanut butter.

The pliable butter traps air pockets, which gives the cookie a lightened consistency. The granulated and dark brown sugar crystals help to incorporate the air. The peanut butter is also added at this step because it has a similar consistency to the butter.

Step 4: Add the Egg and Vanilla

Add the egg and vanilla extract once the butter and sugars are creamed together. Whip on medium setting for about 1 minute.

The mixture should become light brown and look fluffy. The egg whites help to aerate the dense butter. The egg yolks emulsify the dough, helping to bind the cookie and add richness.

Dry oat and flour ingredients added to the stand mixer bowl of wet ingredients.

Step 5: Fold in Flour and Chocolate

I incorporate the flour and oat mixture by hand into the wet ingredients to prevent a tough texture. Give it a good stir with a spatula until no flour pockets remain.

Chocolate chips and M&M candies added to the bowl of dough batter.

Add ¾ cup of M&M candies and chocolate chips and mix until evenly distributed. You don’t have to wait to rest the cookie dough; it’s ready to portion and bake.

Raw cookie dough balls on a parchment paper lined sheet pan.

Step 6: Portion Out the Dough

Portion out the dough into 2 tablespoon-sized rounds. This is about a 1 ounce (30 grams) size. The dough is wet and sticky, making it a drop cookie. It’s best to use a scoop or spoon; it will be challenging to roll. Place the dough at least 2 inches apart; they will spread to about 2 ½ inches in size.

I was able to fit 13 cookies on a large sheet pan. You can either add the extra M&Ms to the dough or after the cookies are baked. The candy shells tend to crack more in the oven, so I add them later while the cookie is warm.

Freshly baked monster cookies on a parchment paper lined sheet pan.

Step 7: Bake the Cookies

For even cooking, bake the cookies one tray at a time, at a moderate oven temperature and in the middle position. I don’t turn the baking sheet halfway through. It’s ready when the surface becomes light golden and the edges set. The baking time is about 10 to 12 minutes.

Person pressing a red M&M into the surface of a warm monster cookie.

Step 8: Add More M&Ms and Cool

Immediately after removing the cookies from the oven, press a few M&Ms on top while they’re soft. This will add a festive pop of color. This step is optional, but once the cookies cool and harden in a few minutes, you won’t be able to add the candies.

Leave the cookies on the warm tray for 5 minutes to gently finish them through carry-over cooking. Transfer to a wire rack to cool completely. These chewy monster cookies have wonderfully crisp edges!

Several fun and festive monster cookies spread out on a table.

Frequently Asked Questions

Can I make these cookies gluten-free?

I recommend using gluten-free oats and gluten-free baking flour. I like Bob’s Red Mill or King Arthur products.

Can I use quick or instant oats instead or old-fashioned?

Quick oats can be used; however, they are precooked with smaller flakes, creating a finer texture with less contrast in texture.

Can I freeze the dough or the baked cookies?

The cookies stay fresh at room temperature in an airtight container for up to 1 week. When stored in a freezer-safe bag, the cookie dough or baked cookies can be kept for up to 2 months.

What is the best peanut butter to use?

A creamy peanut but like Jif or Skippy provides the best texture for the cookie. The processing creates a super smooth consistency, making it much easier to incorporate the nut pieces, fat, and protein into the dough. A small amount of added hydrogenated vegetable oil helps to prevent the fat from separating after baking, keeping it tender. Natural peanut butter, where the oil settles on top, makes it harder to mix into the dough. It can be used, but the shelf life will be shorter by a few days because the fat starts to separate.