Name: Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe
Prep time: 30 min
Cook time: 12 min
Total time: 42 min
Cuisine: American
Ingredients: 2 large eggs; 1 cup (256 grams) creamy peanut butter (such as Jif or Skippy); 2 teaspoons vanilla extract; 3/4 cup (160 grams) packed light brown sugar; 1/4 cup (50 grams) granulated sugar; 3/4 cup (75 grams) old-fashioned rolled oats (certified gluten-free if needed); 1/2 teaspoon baking soda; 1/2 teaspoon kosher salt; 1/2 cup (85 grams) mini semisweet chocolate chips; 1/2 cup (about 85 grams) peanut butter candies (such as Reese’s Pieces), plus a few more for topping; Flaky sea salt, for topping (optional but highly encouraged)

Jump to Recipe· 3.8 from 3 reviews

If you have a soft spot for cookies that are thick, chewy, and bursting with flavor, then you are absolutely going to adore this Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe. Imagine biting into a cookie loaded with creamy peanut butter, hearty rolled oats, melty mini chocolate chips, and candy-coated peanut butter surprises that bring a playful crunch. These cookies bake up with irresistible crispy edges and soft centers that stay chewy, striking the perfect balance between indulgence and comfort. Plus, being flourless and gluten-free, they’re a wonderful treat that feels a little special while still hitting all those classic cookie cravings.

Ingredients You’ll Need

A clear glass bowl sits on a white marbled surface filled mostly with thick, light brown dough with visible oats mixed in. On the right side of the dough is a pile of small, dark brown chocolate chips. Bright candy-coated pieces in yellow, orange, and dark brown are being dropped into the bowl, some mid-air and some resting on the dough. A black spatula with a silver handle leans in from the top right, partially pressed into the mixture while a woman's hand holds the bowl from the left side. The background is blurred with green and yellow shapes. photo taken with an iphone --ar 4:5 --v 7

This Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe calls for a few simple, pantry-friendly ingredients that all play a meaningful role in delivering the texture and rich flavor you love. Each ingredient is thoughtfully chosen to create that perfect chewy yet crisp bite while filling your kitchen with an amazing aroma.

2 large eggs: Acts as the natural binder and provides structure for the cookies.
1 cup creamy peanut butter: Choose a classic like Jif or Skippy for smoothness and that signature peanutty taste.
3/4 cup packed light brown sugar: Adds moisture and depth with a subtle molasses flavor.
1/4 cup granulated sugar: Gives a bit of sweetness and helps with browning for those crisp edges.
2 teaspoons vanilla extract: Enhances all the flavors and adds a sweet, fragrant note.
3/4 cup old-fashioned rolled oats: Provides chewiness and heartiness while keeping it naturally gluten-free.
1/2 teaspoon baking soda: A leavening agent that helps the cookies rise just enough.
1/2 teaspoon kosher salt: Balances the sweetness and intensifies the peanut butter and chocolate flavors.
1/2 cup mini semisweet chocolate chips: Melts into little pockets of chocolate heaven.
1/2 cup peanut butter candies (Reese’s Pieces): Brings that colorful, crunchy pop and fun peanut butter bite throughout.
Flaky sea salt for topping (optional): A finishing touch that magnifies flavor with a delicate salty crunch.

How to Make Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe

Step 1: Prepare Your Oven and Pans

Start by positioning your oven racks in the upper third and center slots, then preheat to 350°F. Don’t forget to line two baking sheets with parchment paper to keep your cookies from sticking and to make cleanup a breeze.

Step 2: Mix Eggs and Sugars

In a large bowl, whisk the eggs until they become slightly frothy and combined. Then add the peanut butter, brown sugar, granulated sugar, and vanilla extract. Stir everything together using a whisk first, followed by a sturdy spatula or wooden spoon. The mixture should be smooth, glossy, and thickly sticky — this is the base that will transform into your tasty cookies.

Step 3: Incorporate the Dry Ingredients

Next, add in the rolled oats, baking soda, and kosher salt. Stir these dry ingredients into the dough until everything is evenly distributed, giving your cookies their chewy texture and just the right lift.

Step 4: Fold in Chocolate and Candies

Carefully fold in the mini semisweet chocolate chips and those irresistible peanut butter candies like Reese’s Pieces. It’s easy to sneak a few here and there, but try to save enough to get plenty of gooey and crunchy surprises in every bite.

Step 5: Chill the Dough

Pop the dough into the fridge for a 20-minute rest. This resting period is key because it allows the oats to absorb some moisture and helps your cookies bake up thick and chewy instead of spreading too thin.

Step 6: Portion and Bake

Use a cookie scoop or tablespoon to drop generous 2-tablespoon mounds of dough about two inches apart on the prepared baking sheets. Press a few extra Reese’s Pieces and chocolate chips on top of each cookie to make them look as irresistible as they taste. Bake for 10 to 12 minutes, rotating halfway through, until the edges look set but the centers are still a touch soft. Remember, pulling them out before fully firming keeps the chewy magic alive.

Step 7: Cool and Finish

Sprinkle the warm cookies with flaky sea salt if you’re using it, then let them cool on the baking sheet for at least 10 minutes. As they cool, the cookies will firm up from soft and gooey into these perfect chewy peanut butter treasures.

How to Serve Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe

A close-up view of a stack of soft, thick cookies with a golden-brown color, showing small cracks on the surface. Each cookie features scattered clusters of small dark brown chocolate chips embedded throughout the dough and bright orange and yellow candy-coated chocolates placed unevenly on the top. The cookies have a slightly textured look with some coarse salt sprinkled lightly. They are laid on a white marbled surface, creating a warm and inviting feel. photo taken with an iphone --ar 4:5 --v 7

Garnishes

A sprinkle of flaky sea salt over these cookies just before serving enhances every dimension of peanut butter and chocolate flavor. A little extra sprinkle of mini chocolate chips or peanut butter candies on the side makes for a festive presentation.

Side Dishes

Pair these cookies with a cold glass of milk, whether dairy or plant-based, to balance the richness. They also go beautifully alongside a cup of hot coffee or tea, making your snack or dessert feel like a cozy moment at home.

Creative Ways to Present

Want to wow guests? Arrange Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe on a rustic wooden board with small bowls of peanut butter, chocolate chips, and candy pieces for a DIY cookie decorating experience. They also make fantastic gift packages when stacked in a pretty tin lined with wax paper.

Make Ahead and Storage

Storing Leftovers

Store any leftover cookies in an airtight container at room temperature for up to four days. This helps keep their chewy texture intact and the flavors fresh. If you want to enjoy them later, they’re just as tasty!

Freezing

You can freeze the dough scoops before baking by placing them on a baking sheet and freezing until firm, then transferring to a zipper bag or airtight container. When you’re ready to bake, pop the frozen dough onto a baking sheet and add a couple of extra minutes to the baking time.

Reheating

To bring back that just-baked warmth, microwave your cookies for 10-15 seconds or warm them briefly in a low-temperature oven. This makes the chocolate melty and the peanut butter delightfully soft.

FAQs

Can I use natural peanut butter instead of creamy?

Natural peanut butter tends to have more oil separation, which can affect how the cookies spread during baking and their final texture. For the best chewy results with perfect shape, creamy peanut butters like Jif or Skippy are recommended.

Are these cookies gluten-free?

Yes! This Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe is naturally gluten-free as it uses rolled oats instead of flour. Just be sure to choose certified gluten-free oats and double-check your candies and chocolate chips for any gluten-containing ingredients.

Can I substitute the peanut butter candies?

Absolutely! While Reese’s Pieces add a classic peanut butter candy crunch, you can swap in M&M’s, chopped peanut butter cups, or even chopped nuts for different textures and flavors.

How large do I make each cookie scoop?

Using about 2 tablespoons per cookie is ideal to achieve a thick, chewy monster cookie with just the right balance of crispy edges and soft centers.

Why do I need to chill the dough before baking?

Chilling the dough allows the oats to soak up moisture, which helps the cookies spread less and maintain their thick, chewy texture instead of becoming flat and cakey.

Final Thoughts

If you’re craving a cookie that feels both nostalgic and a little adventurous, this Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies Recipe is your new best friend. It’s easy to make, packed with flavors and textures that delight every bite, and perfect for sharing with loved ones or treating yourself. Trust me, once you try these chewy peanut butter oatmeal cookies, they’ll quickly become a favorite in your recipe collection too.