Halloween M&M Cookie Bars

These Halloween M&M cookie bars make a deliciously festive treat with the addition of Halloween M&Ms and Halloween sprinkles mixed into a delicious traditional cookie base. They’re the perfect addition to any Halloween party table!

The countdown is on! Just over two weeks until Halloween, and I’m finally sharing the last of my Halloween recipes for the year! Still lots of pumpkin and fall flavors to come but this is the end of the Halloween goodies.

And I may have saved the best for last – I’ll let you choose!

These yummy Halloween M&Ms cookie bars combine a typical cookie base with M&Ms, Oreos, and lots of Halloween sprinkles for not only a delicious but also a super festive treat!

If you like Oreos or cookies and cream flavor, you’re going to love these bars! And if you don’t, maybe try these cookie dough Oreo brownies instead!

They’re also a super easy recipe to share, which means they’re a great Halloween party food or would even be good wrapped up and added to a cute Halloween boo bucket!

Why You’ll Love This Recipe

• Super easy – just dump all the ingredients together, put in a baking dish, and bake! There’s no finesse or delicacy needed in this recipe, making it a great one to make with kids!
• Festive look – these not only have candies and cookies mixed into the dough, but they’re topped with all sorts of festive treats as well, making them perfect for serving at a Halloween get together!
• Cookies and cream flavor – the Oreos give these cookie bars a cookies and cream flavor that is just delicious (assuming you like Oreos anyway). If you want a regular sugar cookie bar recipe, I’ll be sharing one of those soon too!

Ingredients

Ingredient Notes

• M&Ms – this recipe uses the Halloween Cookies and Cream M&Ms but it would be fine with traditional M&Ms as well, just try to find the Halloween colored ones!
• Oreos – I used regular Oreos in this recipe but Double Stuffed would work fine as well. You want your Oreos to be chopped into bite-sized chunks. One cup of the Oreos will go into the cookie dough and the rest will be added on top of the M&M cookie bars.
• Sprinkles – any kind of Halloween sprinkles can be used, I just used what I had on hand!

How to Make M&M Cookie Bars

One of the reasons I love making bars is just how easy they are to make – it’s literally just mix, dump, bake, and cut!

Okay fine, there’s a bit more to it but just a bit.

Start by preheating your oven to 350 degrees and lining a 9×13 baking dish with parchment paper. Lining it with parchment paper not only helps the bars not stick to the pan (since they’re not touching the pan), it also allows you to pull the bars out once they’re cooled to get perfect cuts!

While the oven preheats, whisk your dry ingredients – flour, salt, and baking soda – together in a bowl then set that bowl aside until later.

In the bowl for a stand mixer, cream the butter and sugars together until well combined.

Once they’re combined, add the eggs and vanilla then beat well, scraping down the sides of the bowl with a spatula if necessary to make sure everything gets combined together.

Slowly add in the flour mixture and mix until just combined; don’t over mix.

Finish the dough by folding in one cup of the M&Ms and one of the chopped Oreos. Don’t mix these with a beater or you’ll end up changing the texture, color, and taste of the bars! Folding is key here.

Spread the cookie dough batter evenly into the prepared pan and top evenly with the remaining M&Ms, Oreo pieces, and sprinkles.

Bake in the oven for 24 to 27 minutes or until the edges are just golden. I start checking the bars around 20 minutes because my oven runs fairly hot and you don’t want to over bake them so the edges get burnt.

Let the M&M cookie bars cool in the pan until completely cooled then use the edges of the parchment paper to pull the cookie bars out and place them on a solid surface to cut into squares.

I recommend cutting with a plastic knife and using it to saw through the cookie bars. You can also use a regular knife, just make sure to use a sawing motion rather than just trying to pull through the cookie bars.

Serve in squares once cooled! You can serve these plain or I personally think they’d be really yummy served with a little cookies and cream ice cream – might as well keep the Oreo theme going right?

Expert Tips

Make sure to bake these in a 9×13 baking pan. They’re too thick to cook in a smaller pan and won’t bake properly without being able to spread out and expand.

Store leftover bars (if there are any) in an airtight container for up to three days.

Recipe FAQs

More Halloween Treats

If you like these Halloween M&M cookie bars, you’ll love these other easy Halloween treats!

• Oreo dirt cake – an updated version of a vintage classic – a layered cake topped with dirt and worms!
• Witch hat cookies – the easiest Halloween treat ever but also the cutest!
• Ghost brownies – what happens when you combine a box brownie with a homemade ghost? These treats!
• Halloween dessert board – an easy witch themed dessert board with step by step instructions to cast your spell perfectly!
• Halloween rice krispie treats – boxed rice krispie treats become a decadent treat when combined with a little ghoulish frosting and sprinkles!