These flourless monster cookie bars skip the flour but are packed with oats and peanut butter for big chewy flavor. They’re naturally gluten free and simple to make.
Monster cookies combine all your favorite cookie ingredients into one over-the-top treat — hence the “monster” name. This version turns that idea into a bar and leaves out the flour. The result is a dense, chewy bar held together by peanut butter, oats and eggs, with mini M&Ms and chocolate chips folded in for color and chocolatey bites.
There’s no butter here either — peanut butter provides the richness and texture.
How to make monster cookie bars:
Preheat the oven and line a 9×9-inch pan with parchment. In a large bowl, whisk together eggs, peanut butter, brown sugar, granulated sugar and vanilla until smooth. Stir in old-fashioned oats, baking soda and salt. Fold in mini M&Ms and mini semisweet chocolate chips. The dough will be thick and slightly grainy from the sugar.
Scoop the mixture into the prepared pan and press it evenly into the corners. Smooth the top with a spatula so it bakes uniformly.
How long to bake monster cookie bars:
Bake at 350°F for about 18–22 minutes. Start checking at 18 minutes and remove the bars once the top begins to brown and a toothpick inserted in the center comes out clean.
Let the bars cool completely in the pan before cutting. You can slice them when slightly warm, but waiting at least 30 minutes helps them set and hold together better.
How to store flourless monster cookie bars:
Store the bars in an airtight container at room temperature for up to 3 days. For longer storage, refrigerate up to one week or freeze for up to 3 months. Thaw frozen bars at room temperature.
This is a fun, kid-friendly recipe — little ones can help stir the batter and press it into the pan. For seasonal variation, swap the mini M&Ms for holiday or limited-edition colors and flavors.
I hope you enjoy these bars! If you make them, tag the creators on Instagram to share your photos.
More gluten free cookies:
- Flourless monster cookies
- Gluten Free Chocolate Marshmallow Cookies
- Gluten Free Chocolate Chip Peanut Butter Blondies
Flourless Monster Cookie Bars
Ingredients
- 2 Eggs, plus 1 egg yolk
- 1 Cup Peanut Butter, creamy
- 3/4 Cup Brown Sugar, light, packed
- 1/4 Cup Granulated Sugar
- 2 teaspoons Vanilla Extract
- 1 Cup Oats, old fashioned; use gluten-free oats for GF option
- 1/2 teaspoon Baking Soda
- 1/2 teaspoon Salt
- 1/2 Cup Mini M&Ms
- 1/2 Cup Mini Semisweet Chocolate Chips
Instructions
- Preheat oven to 350°F and line a 9×9-inch baking pan with parchment paper. Set aside.
- In a large bowl, mix the eggs, creamy peanut butter, light brown sugar, granulated sugar and vanilla until combined. Stir in the oats, baking soda and salt, then fold in the M&Ms and chocolate chips. The dough will be thick and grainy.
- Scoop the dough into the prepared pan and spread it evenly to the corners. Bake in the preheated oven for 18–22 minutes.
- Start checking at 18 minutes to avoid over-browning. Remove from the oven and allow the cookie bars to cool completely in the pan before cutting.
- Store in an airtight container at room temperature for 3 days, in the refrigerator for up to a week or in the freezer for up to 3 months.
Recipe Notes
Nutrition
Nutrition information is automatically calculated and should be used as an approximation.
