Flourless Monster Cookies: Chewy Peanut Butter Oatmeal Cookies with Reese’s Pieces and Mini Chocolate Chips Recipe
These flourless peanut butter monster cookies are thick, chewy, and packed with creamy peanut butter, old-fashioned rolled oats, mini chocolate chips, and peanut butter candies like Reese’s Pieces. They bake to perfection with crisp edges, soft centers, and just the right amount of salt to balance the sweetness. Perfect for a hearty, satisfying treat, especially in gluten-free baking.
- Prep Time: 30 minutes
- Cook Time: 12 minutes
- Total Time: 45 minutes
- Yield: About 16 cookies
- Category: Baking, Cookies
- Method: Baking
- Cuisine: American
- Diet: Gluten Free
Ingredients
Wet Ingredients
- 2 large eggs
- 1 cup (256 grams) creamy peanut butter (e.g., Jif or Skippy)
- 2 teaspoons vanilla extract
Dry Ingredients
- 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
- 1/2 teaspoon baking soda
- 1/2 teaspoon kosher salt
Add-ins
- 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
Toppings
- Flaky sea salt, for topping (optional but highly encouraged)
Instructions
- Preheat Oven and Prepare Baking Sheets: Place racks in the upper third and center of the oven, then preheat to 350°F. Line two baking sheets with parchment paper to prevent sticking and ensure even baking.
- Mix Eggs: In a large bowl, whisk together the eggs until well combined and slightly frothy to help incorporate air, which aids in cookie texture.
- Add Peanut Butter and Sugars: Add creamy peanut butter, light brown sugar, granulated sugar, and vanilla extract to the eggs. Use a whisk followed by a sturdy spatula or wooden spoon to mix until the batter is smooth, glossy, and thoroughly combined. The dough will be thick and sticky.
- Incorporate Dry Ingredients: Stir in old-fashioned rolled oats, baking soda, and kosher salt until evenly incorporated throughout the dough for proper texture and leavening.
- Fold in Chocolate Chips and Candies: Gently fold mini semisweet chocolate chips and Reese’s Pieces or peanut butter candies into the dough, saving a few pieces to press on top later.
- Chill the Dough: Refrigerate the dough for 20 minutes. This resting period allows the oats to absorb moisture and helps the cookies bake up thick and chewy.
- Scoop Dough onto Baking Sheets: Use a cookie scoop or spoon to portion out 2-tablespoon-sized mounds of dough, spacing them about 2 inches apart to allow for spreading during baking. The dough will be sticky, so a scoop is handy.
- Add Toppings: Gently press extra peanut butter candies and mini chocolate chips on top of each cookie dough mound to enhance appearance and flavor.
- Bake: Bake the cookies for 10 to 12 minutes, rotating the baking sheets halfway through for even cooking, until edges are set and centers look slightly soft—avoid overbaking to maintain chewy centers.
- Cool and Finish: Immediately after baking, sprinkle flaky sea salt over warm cookies if desired. Let them cool on the baking sheets for at least 10 minutes so they finish setting before transferring to a wire rack to cool completely. The cookies will be soft when warm and firm up to a chewy texture as they cool.
Notes
- Use conventional creamy peanut butter (e.g., Jif or Skippy) to avoid spreading issues often caused by natural peanut butter that separates.
- For gluten-free cookies, use certified gluten-free rolled oats and verify that candies and chocolate chips do not contain gluten.
- Store baked cookies in an airtight container at room temperature for up to 4 days to maintain freshness.
- Dough can be scooped and frozen for later baking; bake frozen dough with an additional 1-2 minutes in the oven.