I’m sharing my Best Monster Cookies Ever with a playful mix of unexpected mix-ins and a secret ingredient that will make you curious.

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I never thought a cookie could be spooky and addictive until I made these Chewy Monster Cookies. Soft and chewy, but with little candy explosions from M&M’s candies and a nutty whisper of creamy peanut butter, they sneak up on you.

I keep telling friends this is the Best Monster Cookies Ever and they roll their eyes but then eat three. Perfect for a Monster Cookies Recipe Halloween spread or any time you need something ridiculous and fun, these are messy, a little over the top, and totally worth it.

Try em if you dare, you might get hooked.

Ingredients

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Peanut butter adds creamy protein and healthy fats, makes cookies rich and nutty
Rolled oats give chewy texture fiber and whole grain carbs, keeps you fuller
Butter brings tenderness and richness, mostly saturated fats for flavor not health
Brown sugar adds molasses sweetness and chewiness, lots of simple carbs and calories
Eggs provide structure and protein plus moisture, helps cookies hold together
M&M’s bring crunch and bright candy sweetness, mostly sugar with artificial dye
Semisweet chips add pockets of melty chocolate and bittersweet flavor contrast
Chopped peanuts add extra crunch and protein, watch salt levels if salted

Ingredient Quantities

1/2 cup (1 stick) unsalted butter, softened

1 cup creamy peanut butter (smooth or chunky)

1 cup packed light brown sugar

1/2 cup granulated sugar

2 large eggs

1 1/2 teaspoons vanilla extract

1 teaspoon baking soda

1/2 teaspoon salt

3 cups old fashioned rolled oats

1 1/2 cups all purpose flour

1 1/2 cups M&M’s candies

1 cup semisweet chocolate chips

1/2 cup chopped roasted peanuts, optional

How to Make this

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1. Preheat oven to 350 F and line baking sheets with parchment paper or a silicone mat, that helps stop sticking and burning on the bottoms.

2. In a large bowl, cream 1/2 cup softened butter, 1 cup peanut butter, 1 cup packed light brown sugar and 1/2 cup granulated sugar until light and a bit fluffy, about 2-3 minutes; using room temp butter and eggs gives a smoother dough.

3. Beat in 2 large eggs one at a time, then stir in 1 1/2 teaspoons vanilla extract until everything is combined, scrape the bowl so no streaks are left.

4. In a separate bowl whisk 1 teaspoon baking soda, 1/2 teaspoon salt and 1 1/2 cups all purpose flour, then add that to the wet mixture and stir just until mostly combined.

5. Fold in 3 cups old fashioned rolled oats, 1 1/2 cups M&M’s, 1 cup semisweet chocolate chips and 1/2 cup chopped roasted peanuts if using; don’t overmix, you want the oats to stay intact so cookies stay chewy.

6. For thicker, chewier cookies chill the dough 20 to 30 minutes in the fridge, or at least 10 minutes; if you’re impatient you can skip this but expect more spread while baking.

7. Scoop dough by heaping tablespoons or a 2-tablespoon cookie scoop onto the prepared sheets, spacing about 2 inches apart, and gently press each mound down just a little so they bake evenly.

8. Bake at 350 F for 10 to 12 minutes, until edges are set and centers still look slightly soft; rotate the pans halfway through for even color.

9. Let cookies cool on the baking sheet for 5 minutes so they set, then transfer to a wire rack to finish cooling; store in an airtight container at room temp for up to 4 days, or freeze for longer.

Equipment Needed

1. Baking sheets (2) — lined with parchment paper or silicone mats to prevent sticking and burning
2. Large mixing bowl for creaming the butter, peanut butter and sugars
3. Medium bowl for whisking the flour, baking soda and salt
4. Electric mixer or sturdy wooden spoon to cream the wet ingredients, mixer makes it faster but spoon works fine
5. Measuring cups and spoons for accuracy, scoop and level the flour
6. Cookie scoop (2-tablespoon) or heaping tablespoon for evenly sized cookies
7. Spatula for scraping the bowl and transferring dough to sheets
8. Wire cooling rack so cookies finish setting and dont steam on the hot pan
9. Cutting board and knife if you plan to chop the roasted peanuts (optional)

FAQ

Q: How do I keep these Monster Cookies chewy and soft? A: Bake at 350 F for about 9 to 11 minutes, pull them when the edges look set and the centers still seem a little soft, they firm up as they cool. Use more brown sugar than white, dont over mix the dough, and chill the dough 15 to 30 minutes if your kitchen is warm, that really helps control spreading and gives a chewier center.

Q: Can I make these cookies nut free if someone has a peanut allergy? A: Yes, swap the peanut butter 1 to 1 with sunflower seed butter or a soy based spread, reduce added salt slightly if the swap is salted. Heads up, sunflower seed butter can sometimes turn baked goods slightly green from a natural reaction with baking soda but its harmless and tastes the same.

Q: Can I use quick oats instead of old fashioned rolled oats? A: You can, but the texture will be different, quick oats make a softer less chewy cookie. For the classic chew use old fashioned oats, if you only have quick oats consider mixing half quick and half rolled for a compromise.

Q: How should I store or freeze the cookies or the dough? A: Store cooled cookies in an airtight container at room temp up to 4 days. Freeze baked cookies up to 3 months, thaw on the counter. You can also freeze scooped dough balls on a tray, then transfer to a bag, bake from frozen adding 1 to 3 minutes to the bake time.

Q: Why did my cookies spread too much and turn out flat? A: Common causes are too warm or over softened butter, not enough flour, or scooping very large rounds. Chill the dough, measure flour by spooning into the cup and leveling, and bake on a cool metal sheet or on parchment, that helps them hold shape.

Q: Want bigger or smaller cookies how do I adjust bake time? A: For tablespoon size scoops bake about 9 to 11 minutes, for larger 2 tablespoon mounds bake about 12 to 14 minutes, adjust by eye and remember its better to underbake a little than overbake if you want chew.

Chewy Monster Cookies Recipe Substitutions and Variations

Unsalted butter: swap with solid coconut oil or vegan margarine, 1:1 by volume (so 1/2 cup). Coconut oil adds a hint of coconut and can make edges a bit crisper, so chill the dough if they spread too much.
Creamy peanut butter: use almond butter or sunflower seed butter 1:1 for a different flavor or nut-free option. If you’re using natural nut butter that’s oily, stir well and pop the dough in the fridge 15-30 min so cookies hold shape.
All purpose flour: replace with whole wheat pastry flour 1:1 for a nuttier, slightly denser cookie, or use a gluten-free 1:1 AP blend (with xanthan gum) same measure if you need gluten free.
M&M’s candies: swap with chopped chocolate bars, mini chocolate chips, or Reese’s Pieces 1:1. For less color bleed press the candies into the tops of the scooped dough instead of mixing them in.

Pro Tips

1) Toast the oats and peanuts first. A quick 5 minute toast in a dry skillet brings out a nutty flavor that makes the whole cookie taste deeper, just make sure they cool completely before folding in so they dont soften the dough.

2) Save a handful of M&M’s and press them onto each cookie just after scooping. They wont get buried or bleed color into the dough and the cookies look way more appealing straight out of the oven.

3) Make ahead by scooping and freezing dough balls on a tray, then bagging them. Bake from frozen and add about 2 to 3 minutes to the bake time so you get thick chewy centers every time.

4) Right after baking sprinkle a little flaky sea salt. It cuts the sweetness and makes the peanut and chocolate flavors pop. Also, use a good peanut butter and dont overmix the dough or the cookies will turn cakey instead of chewy.

Chewy Monster Cookies Recipe

Recipe by Kate Sinclair

0.0 from 0 votes

I'm sharing my Best Monster Cookies Ever with a playful mix of unexpected mix-ins and a secret ingredient that will make you curious.

Servings

servings

Calories

324

kcal

Equipment: 1. Baking sheets (2) — lined with parchment paper or silicone mats to prevent sticking and burning
2. Large mixing bowl for creaming the butter, peanut butter and sugars
3. Medium bowl for whisking the flour, baking soda and salt
4. Electric mixer or sturdy wooden spoon to cream the wet ingredients, mixer makes it faster but spoon works fine
5. Measuring cups and spoons for accuracy, scoop and level the flour
6. Cookie scoop (2-tablespoon) or heaping tablespoon for evenly sized cookies
7. Spatula for scraping the bowl and transferring dough to sheets
8. Wire cooling rack so cookies finish setting and dont steam on the hot pan
9. Cutting board and knife if you plan to chop the roasted peanuts (optional)

Ingredients

1/2 cup (1 stick) unsalted butter, softened
1 cup creamy peanut butter (smooth or chunky)
1 cup packed light brown sugar
1/2 cup granulated sugar
2 large eggs
1 1/2 teaspoons vanilla extract
1 teaspoon baking soda
1/2 teaspoon salt
3 cups old fashioned rolled oats
1 1/2 cups all purpose flour
1 1/2 cups M&M's candies
1 cup semisweet chocolate chips
1/2 cup chopped roasted peanuts, optional

Directions

Preheat oven to 350 F and line baking sheets with parchment paper or a silicone mat, that helps stop sticking and burning on the bottoms.
In a large bowl, cream 1/2 cup softened butter, 1 cup peanut butter, 1 cup packed light brown sugar and 1/2 cup granulated sugar until light and a bit fluffy, about 2-3 minutes; using room temp butter and eggs gives a smoother dough.
Beat in 2 large eggs one at a time, then stir in 1 1/2 teaspoons vanilla extract until everything is combined, scrape the bowl so no streaks are left.
In a separate bowl whisk 1 teaspoon baking soda, 1/2 teaspoon salt and 1 1/2 cups all purpose flour, then add that to the wet mixture and stir just until mostly combined.
Fold in 3 cups old fashioned rolled oats, 1 1/2 cups M&M's, 1 cup semisweet chocolate chips and 1/2 cup chopped roasted peanuts if using; don’t overmix, you want the oats to stay intact so cookies stay chewy.
For thicker, chewier cookies chill the dough 20 to 30 minutes in the fridge, or at least 10 minutes; if you’re impatient you can skip this but expect more spread while baking.
Scoop dough by heaping tablespoons or a 2-tablespoon cookie scoop onto the prepared sheets, spacing about 2 inches apart, and gently press each mound down just a little so they bake evenly.
Bake at 350 F for 10 to 12 minutes, until edges are set and centers still look slightly soft; rotate the pans halfway through for even color.
Let cookies cool on the baking sheet for 5 minutes so they set, then transfer to a wire rack to finish cooling; store in an airtight container at room temp for up to 4 days, or freeze for longer.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.