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    Home » Recipes » Cookies

    Leftover Halloween Candy Bar Cookies (Monster Cookies)

    Modified: Feb 22, 2025 · Published: Sep 10, 2023 by Sarah Jenkins. This post may contain affiliate links. See the Privacy Policy at the bottom of this page.

    Jump to Recipe

    These Halloween Candy Bar Cookies use the best candy to make a delicious and scary treat, perfect for your Halloween party. It’s also a great way to use up all that leftover Halloween candy!

    Halloween Candy Monster Cookies with Monster Eyes.

    Last Halloween, my 2 boys brought home two (2!) large pillowcases filled to the brim with Halloween candy - EACH. They were STUFFED with Kit Kats, Heat Bars, Milky Ways, Reese's Peanut Butter Cups, Jolly Ranchers, Nerds - pretty much any type of Halloween candy you could think of. It was a TON of candy, and there was no way we were ever going to eat it all. 

    We gave most of it away, but still had a bunch of leftover candy so we decided to make a batch of these cookies and put the rest of it to good use. The result? soft, chewy cookies packed with all your favorite leftover Halloween candy. It's the perfect way to use up all of those candy pieces your kids bring home after Trick or Treating. 

    For these yummy cookies, I used the traditional Monster Cookie recipe as a base and just added in the chopped candy bits I thought would go well with the classic peanut butter, oatmeal, and chocolate chip base. I also added some candy eyes to make these extra festive!  

    My family loves these Leftover Halloween Candy Monster Cookies. We had so much fun making these tasty treats!

    In This Post
    • Why these cookies work
    • Ingredients
    • How To Make Leftover Halloween Candy Bar Cookies
    • ​Substitutions
    • Variations
    • What kinds of candies should I use for this candy cookie recipe?
    • Frequently Asked Questions
    • More Great Cookie Recipes
    • Recipe
    • Comments

    Why these cookies work

    • Easy. These cookies are simple to whip up and take only about 10 minutes to bake.
    • Uses up all that extra Halloween candy. Have I mentioned that my kids go a bit crazy on Halloween? This recipe made good use of all the leftover Halloween candies, and now making this sweet treat is one of our favorite things to do come November 1st. 
    • Delicious. If you're like me and have a lot of candy after Halloween, you'll have your pick of the best mini-candy bars on the market!  You can totally customize these cookies with pieces of your favorite candy bars and different kinds of candy.
    • FUN! These cookies really are fun to make and an activity the whole family can get involved in. I love making these cookies with my kids, and they feel so proud to have contributed the most vital ingredients! 
    • Great for parties. These are also great to make BEFORE Halloween if you're having a Halloween party. They're a huge hit with kids! 

    Ingredients

    The ingredients here are simple and you'll most likely have all of them on hand already:

    • Oats. This recipe doesn't use flour - instead, it uses a combination of ground and rolled oats to create a chewy cookie that's soft and gooey in the middle yet still has crispy edges. 
    • Sugars. A combination of white and brown sugar gives these cookies their sweetness
    • Peanut Butter. A staple when making Monster cookies.
    • Chopped Candy Bars! The best part! You can use your favorites but we used a combination of Twix, Snickers, M&Ms, 100 Grand, Reeces, and Milky Ways.
    • Candy Eyes. Totally optional, but they're an adorable fun addition. 

    How To Make Leftover Halloween Candy Bar Cookies

    Making these cookies is fairly easy. The hardest part may just be deciding which leftover candy to use! 

    1. Mix the wet ingredients. To make the cookies, first, mix the sugars, then cream your sugars and butter in a large mixing bowl or a stand mixture. Slowly add in the eggs, vanilla, and peanut butter and stir until combined (this can be done by hand, with an electric mixer, or a stand mixer with a paddle attachment). 
    2. Grind the oats. Using a food processor or high-speed blender (I used my VitaMix), grind 3 cups of the oats until they are a coarse, flour-like consistency. Add them to a medium bowl, then add the remaining 2 cups of oats, baking soda, and salt and stir to combine.
    3. Combine the wet and dry ingredients. In a large bowl, combine the peanut butter mixture with the flour mixture and stir until just combined. 
    4. Add the candy! Next comes the fun part - adding the candy! You can use whatever type of candy you want here, but I stuck to chocolate varieties (omit any mint flavors though, like Peppermint Patties). Chop the candy into small chunks and add them to the cookie dough. 
    5. Make the cookie dough balls. Use a 1.5-tablespoon cookie scoop or a spoon to scoop out the soft cookie dough into balls. Place 6 of them in a single layer on a cookie sheet lined with parchment paper. (These cookies spread a lot so keep the cookies to 6 per tray. If your chunks of candy are big, causing the dough to be a bit crumbly, you may need to reshape your dough balls on the baking sheet by pressing them together. You can also use a spoon to slightly flatten the cookie dough, helping them to all cook a bit more evenly.) 
    6. Bake! Now, they’re ready for the oven. Bake leftover candy cookies at 350 degrees for 10-12 minutes, then promptly remove the baked cookies from the oven (you want them a bit undercooked). If using the candy eyes, press them into the top of the cookie immediately while the cookies are still soft then allow the cookies to cool on the baking sheet for an additional 5 minutes before transferring them to a wire rack to cool completely at room temperature. (Undercooking the cookies slightly and allowing them to cool on your baking sheet will help keep them soft and chewy.)

    ​Substitutions

    • Sub out some of the oats for flour. If you want, you could sub out the ground oats for all purpose flour. I'd still recommend keeping the rolled oats though as they contribute to the chewiness of the cookie. 
    • Sub the candy. Traditional Monster cookies use a combination for traditional chocolate chips and M&Ms so if you want to just stick with those classics, that's totally fine.
    • Vary the peanut butter. Don't want to use peanut butter? Almond butter is a great substitute! 

    Variations

    You can vary these cookies by using different types of candy (candy corn cookies could be a fun twist!). You could also make Leftover Halloween Candy Cookie Bars instead of individual cookies, which would be a fun variation. 

    What kinds of candies should I use for this candy cookie recipe?

    This is really up to you and your preference but my two rules are 1. Don't use anything minty (think peppermint patties) and 2. Don't use anything too fruity or hard (somehow Jolly Ranchers inside of a chocolate and peanut butter cookie don't sound appealing). I typically just use a variety of chocolate bars cut into small pieces. Below are some great options that you'll probably see in your Halloween basket (or that are readily available at the store).

    • Heath bars
    • Kit Kats
    • Reese's peanut butter cups
    • Milky Ways
    • Reese's Cups
    • Snickers Bars
    • M&Ms
    • Reese's Pieces
    • 100 Grand Bars
    • Almond Joys
    • Mounds Bars
    Halloween Candy Monster Cookie - Prep

    Frequently Asked Questions

    How many different types of candy should I use?

    This is really up to you but don't go overboard. At their heart, these cookies are peanut butter, chocolate chip cookies and you don't want to overpower the taste with loads of chocolate. Just pick a mix of your favorite candies. 

    Why is my dough so crumbly? 

    This may be a result of overmixing. If this happens, simply add a little bit of liquid in small amounts (an extra egg or egg yolk, butter or even a splash of milk can help remedy this problem). 

    How do I store leftovers?

    Store any leftovers in an airtight container for up to 4 days. 

    Halloween Candy Monster Cookies On Cooling Rack.

    These Leftover Halloween Candy Bar Cookies are the best way to use up the surplus of Halloween candy you may find yourself with. If you make this delicious treat let me know what you think in the comments below! And don't forget to tag me with a pic @frontrangefed on Instagram so I can see your spooky masterpiece! 

    More Great Cookie Recipes

    • Soft Sugar Cookies
    • Chocolate-Dipped Orange And Almond Shortbread Cookies
    • Vanilla And Maple Snickerdoodle Cookies
    • Soft Pumpkin Cookies With Cream Cheese Frosting
    • The New York Times Chocolate Chip Cookies
    • Chocolate Chip Marshmallow Cookies

    Recipe

    Halloween Candy Monster Cookies

    Leftover Halloween Candy Bar Cookies

    Author: Sarah Jenkins
    This monster cookie recipe uses the best Halloween candy to make a delicious and scary treat, perfect for your Halloween party. It’s also a great way to use up all that leftover Halloween candy!
    4.98 from 48 votes
    Print Recipe Pin Recipe
    Prep Time 15 minutes mins
    Cook Time 15 minutes mins
    Total Time 30 minutes mins
    Course Dessert
    Cuisine American
    Servings 24 cookies
    Calories 326 kcal

    Ingredients
      

    • ½ cup white sugar
    • ¾ cup light brown sugar
    • ½ cup unsalted butter (room temperature)
    • 3 eggs
    • 1 ½ cup peanut butter (smooth)
    • 1 tablespoon vanilla extract
    • 4 ½ cups rolled oats (divided)
    • 2 teaspoon baking soda
    • 1 tsp salt
    • 1 ⅓ cup chopped candy (we used Twix, Snickers, M&Ms, 100 Grand, Reeses and Milky Way)
    • candy eyes
    • ½ cup chocolate chips

    Instructions
     

    • Line two baking sheets with parchment paper or a slip mat and preheat your oven to 350 degrees.
    • Combine the white and brown sugar, and butter in a large mixing bowl with a paddle attachment. Cream sugars and butter until the mixture is well mixed.
    • One by one, add in the 3 eggs and continue to beat on low. Then, add in the vanilla and peanut butter and mix until combined.
    • In a food processor, pulse 3 cups of the oats until they resemble coarse flour. Add in the remaining 2 cups of oats, baking soda, and salt and stir to combine. 
    • Slowly add the dry ingredients to the wet ingredients and mix well.
    • Chop up 1-1 ⅓ cup of chocolate candies into small pieces and add to the cookie batter. If using M&Ms, reserve those until you’ve formed your cookies.
    • Using a scoop, place 6 2 inch balls of cookie dough on each tray, with plenty of space between them. 
    • Flatten the cookies with the back of a spoon and add 2-3 M&Ms to each cookie (if using).
    • Bake the cookies for 12-15 minutes at 350 degrees.
    • If using the candy eyes, add them immediately after you pull the cookies out of the oven, while they are still soft.
    • Allow cookies to cool on the baking sheet for about 10 minutes before transferring to a baking rack to cool completely.

    Notes

    • Don't over bake these cookies. You want them to be slightly undercooked when you take them out of the oven -they'll harden up as they cool.
    • Store cookies in an airtight container for up to 1 week. 

    Nutrition

    Calories: 326kcalCarbohydrates: 36gProtein: 7gFat: 18gSaturated Fat: 7gPolyunsaturated Fat: 3gMonounsaturated Fat: 6gTrans Fat: 0.2gCholesterol: 32mgSodium: 276mgPotassium: 206mgFiber: 2gSugar: 21gVitamin A: 159IUCalcium: 45mgIron: 1mg
    Keyword halloween party, leftover candy
    Tried this recipe?Let me know how it was!

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    Comments

      4.98 from 48 votes (48 ratings without comment)

      Did you try this recipe? I'd love to hear what you think! Leave a comment below! Cancel reply

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      Recipe Rating




    1. Stevan Evans says

      October 28, 2021 at 1:52 am

      "add 2-3 M&Ms to each cookie"; um, the cookie in the picture has four (4) M&Ms. Are you to be trusted, Ms. Fed?

      Reply
    Sarah Jenkins

    Hi, I'm Sarah! I love creating dishes based on what's in season and using local ingredients as often as I can. I hope you'll find some new to you recipes here that will inspire you to make something delicious!

    More about me →

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