Reese’s Stuffed Monster Cookies

by Jillian

How do you make a super soft, thick and chewy cookie filled with M&M’s, Heath Toffee Bits, peanut butter, and oats even better? Stuff a Reese’s Peanut Butter Cup inside!

Reeses Stuffed Monster Cookie

If you’ve never heard of Monster Cookies before, my question to you would be, “Who are you??”

To bring you up to speed, the Monster Cookie is probably the best peanut butter cookie creation of our time. They’re loaded with M&Ms, chocolate chips, oats, and PEANUT BUTTER. PEANUT BUTTER, people. If I could eat nothing but endless jars of Jif or Skippy for the rest of my life, I’d be the happiest girl in the world. Seven-hundred pounds, maybe…but happy!

Monster cookies are called “Monster” for a reason. They’re loaded with amazing gems of deliciousness.

Monster Cookies on pan

Let’s get real. If you’re going to make a cookie with the word, “monster” in the title, you HAVE to make them BIG.

Monster cooke!

One of the great things about Monster Cookies is that you can throw anything in it! Besides meatloaf, of course. Any leftover candy from Halloween–if that’s even a possibility in your household–can easily be thrown in or substituted for the M&M’s or chocolate chips. Since I didn’t have any chocolate chips on hand, I just used a bag of Heath Milk Chocolate Toffee Bits, which I believe made this cookie even better. You got an added crunch from the toffee bits in each bite. Plus, who DOESN’T love the sweet buttery flavor of what I consider to be candy gold?

While there’s definitely nothing wrong with your classic Monster Cookie, I couldn’t help but think of ways to make this tasty treasure even better.

Then it hit me.

REESE’S PEANUT BUTTER CUPS!!!! Why not stuff even more peanut butter ecstasy inside?


You may need an entire gallon of milk to wash down the richness of this peanut butter explosion of a cookie, but it’s TOTALLY worth it.

Peanut Butter Heaven

Before you make a mad dash to your kitchen and knock over any pets or kids in the process, I’ve provided a few step-by-step photos to make your life a little easier.

Once you’ve made up your dough and marveled at the beautiful peanut buttery bliss that sits before you…



…you can get to stuffin’ those PB cups inside!

Below are my steps for stuffing the perfect cookie:

I think I’ll just let the pictures do all the talking for me…






Now that you’ve stuffed your cookies, place them on a parchment-lined cookie sheet. I only put six on a sheet since they were pretty large cookies. I also reserved some of the M&M’s to “bejewel” the top of the cookies.


Pop those babies into the oven for about 14-16 minutes, or until golden around the edges.


Allow your cookies to cool for about 10 minutes before diving into them, or else you’ll end up with a gooey, peanut buttery mess all over your hands. Not that that’s a bad thing…

Reeses Stuffed

Reese's Stuffed Monster Cookies

How do you make a super soft, thick and chewy cookie filled with M&M's, Heath Toffee Bits, peanut butter, and oats even better? Stuff a Reese's Peanut Butter Cup inside!
Prep Time 45 minutes
Cook Time 15 minutes
Total Time 1 hour
Course Dessert
Cuisine American
Servings 20 Cookies


  • 1 cup (230g) unsalted butter, softened to room temperature
  • 1 cup (200g) light brown sugar
  • ½ cup (100g) granulated sugar
  • 1 ½ cup (370g) creamy peanut butter
  • 2 large eggs at room temperature
  • 2 teaspoons vanilla extract
  • 2 ½ cups (320g) all-purpose flour
  • 1 teaspoon baking soda
  • 1 teaspoon salt
  • 1 cup (80g) quick oats
  • 1 (12 oz) bag plain M&M's
  • 1 (8 oz) bag Heath Milk Chocolate Toffee Bits*
  • 2 (10 oz) bags Reese's Peanut Butter Cups unwrapped


  • Preheat oven to 350ºF, and line a baking sheet with parchment paper.
  • In a large mixing bowl, cream the butter and both sugars together until light and fluffy, about 3 minutes.
  • Mix in the eggs (one at a time), peanut butter, and vanilla. Scrape down the sides of the bowl with a rubber spatula as needed.
  • In a separate bowl, mix the flour, baking soda, salt, and quick oats together.
  • Slowly incorporate the flour mixture into the butter mixture. Do not overmix.
  • Fold in the M&M's (reserve a few for tops of cookies) and Heath Toffee Bits by hand.
  • Using a 2-oz ice cream scoop, scoop out some of the dough and release it into the palm of your hand. Take a peanut butter cup in the other hand and gently press it into the dough.
  • Carefully wrap the dough around the peanut butter cup, making sure dough is fully sealed around the cup. Place it onto the baking sheet and press a few more M&M's on top of each cookie, if preferred. Bake for 14-16 minutes, or until golden brown around the edges. Allow cookies to cool on baking sheet for 10 minutes before transferring to a wire rack to cool completely. Store cookies covered at room temperature for up to 1 week.


*Feel free to experiment with other kinds of chocolate candies or chips (chocolate, white, butterscotch, peanut butter, etc.) in this recipe!
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