This Monster Cookie Bars recipe yields soft ‘n chewy peanut butter oatmeal chocolate chip bars packed with M&M’s, chocolate chips and oats! Thick cookie bars with moist centers and crisp edges. Yum!
Why We Love This Recipe
- Thick & Chewy: Thick cookie bars have decadent chewy edges, just like oatmeal cookie bars!
- Moist & Just-Baked: Mouthwateringly moist and soft with just-baked centers that are almost like cookie dough.
- Crowd-Pleaser: Everyone loves these M&M-packed monster cookie bars (like they do chocolate peanut butter cupcakes).
Monster Cookie Bars Recipe
Okay, can I tell you how excited I am about today’s monster cookie bars recipe?? It’s got everything you could hope for: big peanut butter flavor, chewiness from chewy edges, two kinds of oats, a hint of a special ingredient, and LOADS of M&M’s and chocolate chips!
This monster cookie bar recipe is my faves because every time I make a batch, everyone asks for more (including me haha!!). It’s easy to make and even easier to eat. What more could you need? Let’s bake this!
Monster Cookie Bars Ingredients
- Peanut Butter: we’re using 1 whole cup to truly amp up the delicious peanut butter flavor, like we do in peanut butter frosting
- Sugar: the combination of cane sugar and brown sugar adds the right amount of crispness and chewy molasses flavor
- Butter: remember to use unsalted butter softened to room temperature
- Maple Syrup: our secret ingredient, which increases chewiness and adds a delicious warmth
- Vanilla: make sure to use pure vanilla extract, as imitation does not taste great
- Oats: half rolled oats for signficant chewiness while half quick oats blend seamlessly into the cookie dough.
- M&M’s & Chocolate Chips: plenty packed into the dough, and lots loaded on top, because seeing is believing. 😉
How to Make Monster Cookie Bars
- Preheat oven to 350°F. Line two 8-inch square baking pans with parchment paper
- Cream together peanut butter, both sugars, and butter with a hand mixer. Beat in eggs one at a time, then maple syrup and vanilla.
- Stir in flour, both oats, baking soda and salt. Fold in M&M’s and chocolate chips.
- Transfer monster cookie dough into the two pans, flattening into an even layer. Press toppings into bars and bake for about 26 minutes. Cool cookie bars, slice and enjoy!
How to Customize
This monster cookie bars recipe is so easy to customize to your liking! You can swap everything from the peanut butter to the chocolate chips and M&M’s.
- Swap the Chocolate Chips: instead use white chocolate chips or peanut butter chips.
- Swap the M&M’s: for your favorite candy, like mini peanut butter cups or Reese’s Pieces.
- Use Another Nut Butter: instead of peanut butter, use almond butter or cashew butter.
Storing Instructions
Room Temperature: After cooling completely, store bars in an airtight container for 1-2 weeks in the pantry or in the fridge.
Can you freeze monster cookie bars? You can freeze these peanut butter oatmeal cookie bars for up to 3 months. Be sure to store them in an airtight, freezer-friendly container. Thaw until M&M’s are soft enough to bite into before enjoying.
For more delicious recipe ideas like monster cookie bars, follow us on TikTok, Instagram, Facebook, and Pinterest. If you’ve tried this recipe, take a pic and tag us on Instagram using #beamingbaker. We can’t wait to see it! Sending you all my love and maybe even a dove, xo Demeter ❤️
Prevent your screen from going dark
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Preheat oven to 350°F. Line two 8-inch square baking pans with parchment paper or greased foil.
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In a large bowl, add peanut butter, granulated sugar, brown sugar, and butter. Using a hand mixer, beat until creamed together. Beat eggs in one at a time until well mixed. Then, beat in maple syrup and vanilla.
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Using a spatula, stir in flour, rolled oats, quick oats, baking soda and salt until you get a cohesive dough. Fold in M&M’s and chocolate chips.
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Split dough equally into the two lined baking pans. Smooth into an even layer. Press toppings into the cookie bars. Bake for 24-28 minutes, until brown at the edges with a crisped top. Mine took 26 minutes.
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Cool in pan for 20 minutes, then transfer to directly onto a cooling rack to cool completely. Slice into 16 bars per pan. Enjoy!
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★ Last Step: If you made this recipe, leave a comment and review. It truly helps our small business keep running and it helps readers like you!
- Storing Instructions: Cool monster cookie bars completely, then store in an airtight container in the pantry for 1-2 weeks.
- Freezing Instructions: After cooling bars, place in a freezer-friendly container and freeze for 1-3 months.
Calories: 179kcal, Carbohydrates: 20g, Protein: 4g, Fat: 10g, Saturated Fat: 4g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 3g, Trans Fat: 0.1g, Cholesterol: 16mg, Sodium: 142mg, Potassium: 105mg, Fiber: 2g, Sugar: 13g, Vitamin A: 90IU, Vitamin C: 0.04mg, Calcium: 23mg, Iron: 1mg
Nutrition information is automatically calculated, so should only be used as an approximation.
