These Thick and Chewy Monster Cookies are loaded with peanut butter, oats, M&M's and chocolate chips. They’re a cross between a chewy oatmeal chocolate chip cookie, and a peanut butter cookie, and they’re sure to be a huge hit with family and friends.
I LOVE making cookies, and since I don't usually have fresh-baked cookies available on the spot, I like to freeze them for when friends come over or when we just want a little treat. In my freezer currently are Jumbo Chocolate Chip Cookies, Red Velvet Sandwich Cookies, and Chewy Pumpkin Chocolate Chip Cookies. Who wants to come over?!
Monster Cookies
Don't ask me to choose a favorite type of cookie because I just wouldn't be able to! There are too many fun variations. These Monster Cookies are always popular and I love the great texture from the oats and the subtle peanut butter flavor.
Why are they called Monster Cookies?
There’s not an exact answer for why these cookies are called “Monster” Cookies. Some people think it’s because they look like monsters, with their bumpy texture and fun colors. I like to think it’s because they’re stuffed with so much “stuff”, making them the “monster” of all cookies.
Whatever the reason, all Monster Cookies have these ingredients in common: peanut butter, oats, chocolate chips and m&m chocolate candy.
How to make Monster Cookies:
- Cream the butter and sugars. Use REAL butter and cream it with the sugar for at least 2-3 minutes until really light and fluffy. This is adding air to the mixture and is the base for the texture we want in our cookies.
- Mix wet ingredients. Add the peanut butter and mix well. Add egg and vanilla and mix.
- Measure flour properly and mix dry ingredients. When measuring the flour be sure to fluff it a bit first, allowing air to fill in (like sifting) before you spoon it lightly into the measuring cup. Stir together the flour, oats, salt, baking powder and baking soda. Stir into wet mixture with m&m's and chocolate chips.
- Slightly under-bake. Bake at 350, being careful not to over bake the monster cookies. The tops will look just set and they will continue to harden and set up as they cool on the baking sheet.
How do I keep my cookies from spreading?
During baking, cookies naturally spread, but the key is to make sure they don't spread too much. To keep your monster cookies from spreading, be sure to use exact measurements (no guesstimating) and use room temperature ingredients, particularly the butter and eggs. You can also stop cookies from getting flat by chilling the dough for 15-30 minutes before baking.
Storage and Freezing Instructions:
These cookies will keep well in an air-tight container for 1-2 days, or you can freeze the cookie dough or baked cookies. To freeze them after they’re baked, allow them to cool completely and store them in a freezer safe container for up to 3 months. Freeze cookie dough balls in a freezer safe container and when ready to bake, place the frozen cookie dough on a baking sheet and add 2-4 minutes to the baking time.
CONSIDER TRYING THESE POPULAR COOKIE RECIPES:
- Jumbo Chocolate Chip Cookies
- Super Soft Sugar Cookies
- Triple Chip Blondies
- M&M Cookie Bars
- Chocolate Mint Cookies
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Recipe
Thick and Chewy Monster Cookies
Equipment
- Stand Mixer optional
Ingredients
- 1/2 cup butter (115 g)
- 1/2 cup granulated sugar (100 g)
- 1/2 cup light brown sugar (110 g)
- 1/2 cup peanut butter (130 g)
- 1 egg
- 1 teaspoon vanilla extract (5 ml)
- 1 cup all-purpose flour (120 g)
- 1 1/4 cups old-fashioned rolled oats (112 g)
- 1/4 teaspoon salt (1.5 g)
- 1/2 teaspoon baking powder (2 g)
- 1/2 teaspoon baking soda (2.5 g)
- 3/4 cup M&M candies (130 g)
- 1/2 cup semi-sweet chocolate chips (90 g)
Instructions
- Preheat oven to 350 degrees F.
- Cream the butter and sugar together really well—at least 2-3 minutes until light and fluffy.
- Add peanut butter and mix well. Add egg and vanilla and mix.
- In a separate mixing bowl stir together the flour (be careful to measure correctly, spooning the flour into a measuring cup, then leveling off), oats, salt, baking powder and baking soda.
- Add to the wet mixture and mix to combine. Stir in chocolate chips and M&M’s.
- Bake at 350 degrees for 10-12 minutes, or a little longer if you make them bigger than a 1 inch cookie scoop. Don't over bake--they will look just set.
- Remove them from the oven and allow them to cool completely on the pan.
Notes
Nutrition
HAVE YOU TRIED THIS RECIPE?!
RATE and COMMENT below! I would love to hear your experience.
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OMG, these cookies are to die for. 10/10 would recommend. the only part I regret is eating them all. haha 😅
I should have never made these cookies because they are so so delicious and I will eat them all!!
Every year I do a “bake off” where I try several recipes of the same type of cookie. This year was monster cookies, and this came out the winner! Best of the top four recipes on the internet. Thanks for sharing!
BEST MONSTER COOKIES EVER! They’re crisp on the outside and chewy on the inside. We used the pack of M&M’s with peanut, peanut butter, and regular in it and it was a great choice.
I love monster cookies so much and these are delicious. Nice and chewy they don’t get hard if they sit out or in the fridge. They’re literally perfect.
I have made this recipe so many times and decided it was time to comment. These are the best monster cookies. thank you. we make them all the time.
These cookies are so good! The recipe made a perfect amount to bake these up quick last night per a request from my 6 yr old. I flatten the first in the oven after they baked and only need to remember to flatten before the oven. This recipe is a keeper!
Family favorite! Perfect combination of chocolate and peanut butter. The light crispiness of the cookies makes it that much better! I do flatten the tops when there’s about three minutes left.
We’ve already made these twice in the last couple weeks!! I was craving monster cookies & these hit the spot #pregnant. My boys and husband also loved them! We added peanut butter m&Ms and Reese’s pieces this time too! SO GOOD!
I have been making monster cookies for years using a famous/well known recipe. I decided to try a different recipe this year because I didn’t want the cookies to spread. So, I found your recipe and baked them last night. These were not only beautiful right out the oven, they were the best tasting monster cookies I have ever made. Thanks for sharing your recipe. I am making them again tonight.
I made a double batch these and they looked like gold balls too. I realized that I forgot to add the brown sugar when I was putting ingredients away. I also ended up quadrupling the m & ms by accident. Anyway, they were still good and I flattened the tops as you advised. I think I was thrown off when mixing the sugar and butter because it did not list to add “sugars.” Clearly I need all the help I can get when following recipes especially when doubling the recipe! Thank you for this recipe.
Should I grease the cookie sheet before placing the cookie dough?
You can line it with parchment paper, or if you don’t have parchment paper you can lightly grease the pan.
Best cookies ever, everything I like in a cookie. I used extra crunchy peanut butter.
I made these and they looked like a golf ball after 12 minutes in the oven. I re-read the recipe to see if I had did something wrong and made them the next day. The same thing happened. Why are they not spreading when cooked? I love all your recipes. This is the first one that has failed for me twice!
Hi Donna, I’m so sorry! What is your altitude? I wonder if you’re higher than I am here in Arizona. Next time you could flatten the tops before baking.
I made these for our Memorial Day BBQ and they were really good! Thank you for the great recipe.
Happy to hear it! Thanks Michelle!
sharing on the weekend edit ! I love a good monster cookie, laura