Making your favorite cookie in a GIANT version just seems like the right thing to do. 😉 We are a huge fan of Monster Cookies and absolutely can’t get enough of this extra big version! Hope you love Giant Monster Cookies as much as we do! Be sure to check out even more of my Cookie Recipes

Monster Cookies on White Plate

Monster Cookies

Why do we call these monster cookies? Well, I have a few ideas.

  1. At least as far as this recipe goes, these giant monster cookies are monstrous in size! Each cookie uses 1/2 cup of monster cookie batter and bakes into a cookie that is bigger than your palm.
  2. Since monster cookies are essentially a cross between two of America’s favorite cookies – the oatmeal cookie and the peanut butter cookie – if you spot someone eating one, your green-eyed jealousy monster is likely to say hi!
  3. This cookie recipe is so easy that even a monster could make them! And, while it does make it a little bit easier to make them in a stand mixer, you definitely don’t need to own one to make this monster cookie recipe!
  4. The M&Ms make them look a little bit like monsters. If monsters looked like cookies, that is.
Giant Monster Cookies stacked on White Plate

When making these giant monster cookies, here a few tips you may find:

  • Toast the oats! Toasting the oats brings out their flavor a little bit more against the peanut butter. If you don’t like the flavor of oats, but just prefer their texture, don’t toast them.
  • Let the batter sit for an hour at room temperature. You don’t have to do this, but letting the batter sit, you hydrate the oats, which I found resulted in a better texture when baked.
  • When you remove these from the oven, you may notice the giant monster cookies won’t look totally baked. They’ll continue baking a little on the cookie sheet. It is important not to overbake these cookies!
  • This one is optional but add a little spice. I added 1/2 teaspoon of cinnamon to add a bit more complexity to the flavor of the final cookie.
Monster Cookie Recipe Stacked and Top Cookie Broken in Half

Can I Make the Cookies Smaller?

You can! The giant monster cookies use a 1/2 cup of batter per cookie, but you can size them down to 1/4 cup or 2 Tablespoons for smaller monsters. You will have to reduce the cooking time.

It’s easy to make a few tweaks to the recipe to satisfy your craving. Swap the chocolate chips for peanut butter chips for even more peanut butter flavor. Or, customize the M&Ms for the holiday! Red and Green for Christmas; pink, red, and white for Valentine’s Day; or pastels for Easter. I like to add more M&Ms on top to make them even super decorative.

Giant Monster Cookie Recipe On Cooling Rack

Can I Make these Cookies Gluten-Free?

I believe they can, but I haven’t yet tested it. If you use gluten-free oats and substitute the flour for 1:1 flour, the recipe should work. This will change the texture slightly.

Giant Monster Cookies with M&Ms
4.75 from 12 votes

Giant Monster Cookies

Prep Time 1 hour 10 minutes
Cook Time 30 minutes
Total Time 1 hour 40 minutes
Making your favorite cookie in a GIANT version just seems like the right thing to do. 😉 We are a huge fan of Monster Cookies and absolutely can't get enough of this extra big version!


  • 2 cups (300 g) oats, preferably not quick oats
  • ¼ teaspoon baking powder
  • 1 teaspoon baking soda
  • 1 cup (128 g) all-purpose flour
  • ¼ teaspoon kosher salt
  • ½ teaspoon ground cinnamon, optional
  • ½ cup (1 stick / 113 g) unsalted butter, softened
  • ¼ cup (57 g) granulated sugar
  • ¾ cup (150 g) brown sugar, packed
  • 1 cup (226 g) creamy peanut butter
  • 2 teaspoons vanilla extract
  • 2 large eggs, room temperature
  • 1 cup M&Ms, divided (mini M&M's work great as garnish as well)
  • ½ cup chocolate chips


Toasting the Oats (Optional)

  • Preheat oven to 350°F.
  • Place oats on baking sheet and toast for 12 minutes, rotating pan halfway through. Remove and let cool on cooling rack.

Monster Cookie

  • Combine oats, baking powder, baking soda, flour, salt, and cinnamon in medium bowl. Set aside.
  • Combine butter, sugar, brown sugar, and peanut butter in bowl of mixer until fully mixed, about three minutes at medium speed.
  • Add eggs, one at a time, mixing for 30 seconds after each addition.
  • Add vanilla extract.
  • Reduce mixer speed and add oat mixture. Mix just until combined.
  • Add ½ cup M&Ms and ½ cup chocolate chips.
  • Cover bowl with plastic wrap and let rest at room temperature for one hour.
  • Preheat oven to 350°F. Line a baking sheet with parchment paper.
  • Use ½ cup measuring cup to portion cookies and place on the lined baking sheet. Cover individual cookies with remaining M&M's.
  • Bake for 16-20 minutes or until edges are slightly golden brown. Remove from oven and let cool.

Did you make this recipe?

Thank you for making my recipe! You took pictures, right? Well go ahead and post them on Instagram! Be sure to mention me @iambaker and use the hashtag #YouAreBaker.

Photos, some copy, and recipe are from Rebecca Swanner of Let’s Eat Cake!

Share with your friends!

Categorized in:

Related Recipes

Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. I see that 90% of replies are women, so as a man who makes these cookies once every 6 months I use a premixed oatmeal cookie mix in grocery store. Then add crunchy pb , MM’s; mini choc chips, reeses pieces. I see no difference from scratch and removes headache and i get to use my wifes kitchen aid stand alone mixer. Also put oven in convection mode.

  2. I went over everything and can’t figure out why my cookies did not spread at all. What could have happened. So bummed out with the time and effort. I am not new at baking.

  3. I’ve tried many versions of monster cookies and this are one of the best. The cookies are thick and firm, with a slight crunch from the oats. The peanut butter is subtle but noticeable. The cinnamon is a nice addition. I used the weight measures for all ingredients, with the exception of the oats. Two cups of old-fashioned oats weighed 180 grams, which is considerably less than the 300 grams noted in the recipe. The dough would have been too dry and crumbly with 300 grams of oats. I measured several times to make sure that I wasn’t reading the weight incorrectly. The cookies are slow to spread. I used 1/4 cup dough per cookie and pressed the scooped dough into a thick disk before baking. They baked for 14 minutes. A light sprinkling of Maldon salt flakes after the cookies came out of the oven added a nice salty touch.

Leave a Reply

Your email address will not be published. Required fields are marked *

Recipe Rating

This site uses Akismet to reduce spam. Learn how your comment data is processed.