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Homemade soft-baked Halloween Monster Cookie Bars are the best Halloween treat to make for a classroom party or a sweet treat for anytime! Traditional monster cookie bars loaded with peanut butter, chocolate, oats, Halloween mix M&M’s, and edible candy eyeballs. So spookily delicious!
For another easy halloween party treat try these Witch Hat Cookies.
Halloween Monster Cookie Bars Recipe
These Halloween monster cookie bars are loaded with all the good stuff – oats, peanut butter, chocolate, Halloween candy, and candy eyeballs. They’re the perfect way to celebrate the ‘spooky’ Holiday coming up.
I also love making these bars with leftover halloween candy from my kids’ bags. Use any combination of candy you want! The options are endless with this delicious recipe that produces thick, soft-baked cookie bars.
Ingredients Needed To Make Halloween Cookie Bars
- All-Purpose Flour
- Old-Fashioned Oats : These are the whole oats and not the quick oats. Although, quick oats can be used if you prefer the smaller/finer texture of them.
- Baking Soda
- Creamy Peanut Butter : For best results, use regular creamy peanut butter and nothing that has the thick oil layer on top or anything labeled ‘all-natural’ or ‘no-stir’ varieties.
- Granulated Sugar
- Light Brown Sugar
- Large Eggs
- Vanilla Extract
- Halloween Ghoul’s Mix M&M’s
- Chocolate Chips
- Peanut Butter Chips
- Edible Candy Eyeballs
How To Make It
Preheat the oven to 350 degrees F. Line a 9×9-inch square baking pan with parchment paper or spray with nonstick cooking spray. Set aside.
In a small mixing bowl, whisk together the flour, oats, baking soda, and salt. Set aside.
In a larger mixing bowl, using an electric hand mixer (or use a stand mixer with the paddle attachment), beat the butter, peanut butter, granulated sugar, and light brown sugar on medium speed until light & fluffy. Beat for at least 2 minute for the best fluffy texture and light color.
Scrape down the sides of the bowl with a rubber spatula and beat in the eggs and vanilla extract just until mixed in.
Scrape the bowl again and then dump in the dry ingredients. Mix on low speed just until combined. Do not overmix, just mix gently until no flour streaks remain in the dough.
Stir in the M&M’s, chocolate chips, and peanut butter chips just until mixed in.
Press the cookie dough into the prepared pan and smooth the top with a spoon or spatula. If you reserved some of the candy and chocolate chips, gently press those into the top of the bars.
Bake for 20-25 minutes or until the edges have set and a toothpick inserted into the center comes out clean.
While the bars are still warm from the oven, immediately press the candy eyeballs into the bars. Allow the bars to cool completely on a cookie sheet before cutting them. About 30 minutes to 1 hour.
How To Store Leftover Halloween Cookie Bars
- Room Temperature : Store leftovers inside an airtight container, at room temperature, for up to 3 days. Eat them at room temperature or for best results microwave it for a few seconds to warm it up and soften it.
- Freezer : To freeze, wrap each square inside plastic wrap and then again tin foil. Place the wrapped cookie bars inside a freezer-safe container for up to 3 months. I recommend leaving the candy eyeballs off the cookie bars if you’re planning on freezing them. The moisture from the freezer can cause the black pupil on the eyeballs to bleed, making the eyeballs scary looking, but not in a good way!
Substitution & Variation Ideas
- Crunchy Peanut Butter : If you want some crunch & texture try using crunchy peanut butter instead of creamy peanut butter.
- Don’t Have Candy Eyeballs? : That’s ok! Simply leave them off. Instead of adding candy eyeballs to the warm cooked bars, try pressing in some additional candies like m&m’s, peanut m&m’s, or peanut butter m&m’s – all in the Ghoul’s M&M’s Mix colors.
- No Peanut Butter Chips? : If you don’t have peanut butter chips then add an additional 1/2 cup of chocolate chips instead.
- Chocolate Chips : Use milk chocolate, semi-sweet chocolate, or dark chocolate chips. You can even mix & match and use some of each if wanted!
- Halloween Candy : The recipe calls for 1 cup of candy but feel free to use any Halloween candy you want. Make sure they’re about the same size of the m&m’s, so chop the candy if needed. You can also use half m&m’s + half chopped Reese’s Bats or something like that.
Recipe Tips For Success
- Don’t Overmix the Cookie Dough : Just mix the dough together until no flour streaks remain in the dough. Don’t mix anything beyond that or else the bars will turn out dry and dense. We want them nice & soft!
- Whip Butters + Sugars : To help achieve soft-baked cookie bars it’s important to really whip the butter and sugars for at least 2 minutes. You want the mixture to look fluffy, light, and much paler in color. This is why I always recommend using a stand mixer because you can let it whip the butter and sugars on it’s own.
- Candy Eyeballs Tips : Do not add the candy eyeballs until right after baking, or they will melt in the oven and not look like eyeballs anymore. You do, however, want to press them into the warm cookie bars immediately after removing the pan from the oven. If the bars are too cold or not warm from the oven, the eyeballs will have a harder time sticking to the tops of the bars, which means they will fall off.
- Thinner Bars : If you want the monster cookie bars not as thick then try using a 9×13 baking pan. I think the 9×9 baking pan makes the perfect soft-baked, thick cookie bar.
- Cutting Bars Into Squares : Allow the bars to cool completely before cutting them into squares. This will help them cut more evenly and cleanly, and prevent them from crumbling or breaking when cut warm.
Halloween Monster Cookie Bars
- 2 cups all-purpose flour
- 1½ cups whole old-fashioned oats
- 1 teaspoon baking soda
- ¼ teaspoon salt
- 1/2 cup (1 stick) butter softened
- 1/2 cup creamy peanut butter
- 1/2 cup granulated sugar
- 1/2 cup packed light brown sugar
- 2 large eggs
- 2 teaspoons vanilla extract
- 1 cup Ghoul's Mix Halloween M&M's
- 1/2 cup chocolate chips
- 1/2 cup peanut butter chips
- candy eyeballs
- Preheat the oven to 350℉. Line a 9×9-inch square baking pan with parchment paper or spray with nonstick cooking spray. Set aside.
- In a small mixing bowl whisk together the flour, oats, baking soda, and salt. Set aside.2 cups all-purpose flour, 1½ cups whole old-fashioned oats, 1 teaspoon baking soda, ¼ teaspoon salt
- In a larger mixing bowl using an electric hand mixer, or use a stand mixer with the paddle attachment, beat the butter, peanut butter, granulated sugar, and light brown sugar on medium speed until light & fluffy. *Beat for at least 2 minute for the best fluffy texture and light color.1/2 cup (1 stick) butter, 1/2 cup creamy peanut butter, 1/2 cup granulated sugar, 1/2 cup packed light brown sugar
- Scrape down the sides of the bowl with a rubber spatula and beat in the eggs and vanilla extract just until mixed in.2 large eggs, 2 teaspoons vanilla extract
- Stir in the M&M's, chocolate chips, and peanut butter chips just until mixed in.* I recommend setting aside about 1/4 cup m&m's and some of the chocolate chips and peanut butter chips to decorate the tops of the bars with in the next step.1 cup Ghoul's Mix Halloween M&M's, 1/2 cup chocolate chips, 1/2 cup peanut butter chips
- Press the cookie dough into the prepared pan and smooth the top with a spoon or spatula. If you reserved some of the candy and chocolate chips, gently press those into the top of the bars.
- Bake for 20-25 minutes or until the edges have set and a toothpick inserted into the center comes out clean.
- Remove the pan from the oven. While the bars are still warm, immediately press the candy eyeballs into the bars. *Allow the bars to cool completely, inside the pan, before cutting them. About 30 minutes to 1 hour.candy eyeballs