These soft, chewy M&M Cookie Bars are the ultimate sweet treat and super easy to make. Perfect for a movie night in, to serve to a crowd, or to have stocked in the freezer for when the sweet tooth hits!
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Enjoy a fun twist on your typical cookie with these delicious bars! They’re thicker than the average cookie and are even simpler to make. You can put together a big batch of these chewy, chocolatey cookie bars in little to no time to serve for a movie or game night, your next cookout, or anytime you crave something sweet.
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Why You’ll Love This Recipe
- They are delicious – these M&M cookie bars are everything you could want in a dessert: soft, chewy, and oh-so-buttery.
- Easy to make – without any mixer or dough rolling, these bars come together quickly and easily.
M&M Cookie Bar Recipe Ingredients
With just a few ingredients on the list, these cookie bars are a cinch to make! Find ingredient notes (including substitutions and swaps) below.
- Gluten-Free or All-Purpose Flour – this recipe works great with King Arthur Measure for Measure flour, Bob’s Red Mill 1-to-1 flour, or regular ole all-purpose flour if you tolerate gluten!
- Brown Sugar – use 1 cup of brown sugar for these delicious, chewy bars. It lends a deep, caramel-like flavor that makes these so good! You can totally use coconut sugar in place of brown if you’d like.
- M&Ms – while we used 1 cup of traditional M&Ms, there are also dye-free options if preferred or festive seasonal M&Ms for a holiday party!
A full ingredient list with exact amounts can be found in the recipe card below.
Recipe Variations and Modifications
- Make it gluten-free – our favorite gluten-free flours are King Arthur Measure for Measure and Bob’s Red Mill 1-to-1, and this recipe works beautifully with both!
- Make refined sugar-free – to make these cookie bars refined sugar-free, just use coconut sugar in place of the brown sugar and dark chocolate chips instead of M&Ms.
- Make it egg-free – we tested different egg substitutes in several different baked goods, took all kinds of notes, and then laid it all out for you in this super helpful guide to egg-free baking. For bars, we recommend using an egg replacer combo: one chia egg (1 tablespoon of milled chia seed + 3 tablespoons of water) and plain Greek yogurt (¼ cup). This combination produced bars that were soft on the inside, crispy on the outside, with a delicious flavor. If you’re looking for a vegan substitute, leave out the Greek yogurt and add another chia egg for a crispy yet dense bar!
How to Make M&M Cookie Bars
A quick whisk, stir, and bake is all it takes for these cookie bars to be ready for your enjoyment! Follow along below.
Step 1: Preheat the oven to 325°F and grease an 9×9 pan with butter, or line with parchment paper. Whisk the butter, eggs, sugar, and vanilla extract together in a large bowl.
Step 2: Add the flour, baking soda, and salt to the bowl and stir to combine. Once the flour is fully incorporated, mix in the M&Ms.
Step 3: Press the mixture into the bottom of a 9×9 pan, and bake for 30-35 minutes, until the top is browned and a toothpick inserted into the center of the pan comes out clean.
Step 4: Slice and enjoy!
Recipe Tips
- Don’t over-pack your flour – when you’re measuring flour for a baked good, use a dry measuring cup to scoop the flour, then even it off (letting any extra flour fall back into the bag) using a butter knife. Don’t press your flour into the measuring cup – this will pack it in, and you’ll end up with too much flour.
- Don’t overmix – be sure to mix the ingredients just until they’re incorporated. Overmixing often results in gummy or overly chewy baked goods!
- Use a metal pan – metal pans are best for these cookie bars because the metal heats up quickly, and allows the outside of the cookie bars to get golden brown.
- Add some extra M&M’s on top – for some added decoration, place a few M&M’s on top of the dough before baking or press a few on top right after you take the cookie bars out of the oven.
How to Serve
Serve these cookie bars warm on their own or with a scoop of your favorite ice cream or whipped cream. Pair these sweet treats with a tall glass of cold milk or a cup of freshly brewed hot coffee.
How to Store and Reheat
Store any leftover cookie bars in an airtight container on the counter for up to five days. These M&M cookie bars can also be wrapped in parchment or wax paper and stored in a Ziplock bag in the freezer for up to 3 months. To warm a frozen cookie bar, just pop it in the microwave for 30 seconds, or until soft and warm!
Frequently Asked Questions
Totally! They’ll just be a bit thicker, so they may need a few extra minutes in the oven. You’ll know they’re finished when a toothpick inserted into the middle of the pan comes out clean.
Of course! Chocolate chips melt a little bit more than M&Ms, so your final product will have more chocolate throughout (rather than just the M&M bites), but they’ll still be divine!
More Favorite Dessert Recipes
If you tried these M&M Cookie Bars or any other recipe on my website, please leave a 🌟 star rating and let me know how it went in the 📝 comments below!
M&M Cookie Bars
Ingredients
- ½ cup 4 ounces butter, melted
- 1 cup brown sugar, 192 grams
- 1 teaspoon vanilla extract
- 2 eggs, room temperature
- 1½ cups all-purpose flour (we used King Arthur for gluten-free!), 186 grams
- ½ teaspoon baking soda
- ½ teaspoon coarse sea salt, or ¼ teaspoon fine salt
- 1 cup M&Ms
Instructions
- Preheat the oven to 325°F and grease an 9×9 pan with butter, or line with parchment paper.
- Whisk the butter, eggs, sugar, and vanilla extract together in a large bowl.
- Add the flour, baking soda, and salt to the bowl and stir to combine. Once the flour is fully incorporated, mix in the M&Ms.
- Press the mixture into the bottom of a 9×9 pan, and bake for 30-35 minutes, until the top is browned and a toothpick inserted into the center of the pan comes out clean.
Recipe Notes
- Don’t over-pack your flour – when you’re measuring flour for a baked good, use a dry measuring cup to scoop the flour, then even it off (letting any extra flour fall back into the bag) using a butter knife. Don’t press your flour into the measuring cup – this will pack it in, and you’ll end up with too much flour.
- Don’t overmix – be sure to mix the ingredients just until they’re incorporated. Overmixing often results in gummy or overly chewy baked goods!
- Use a metal pan – metal pans are best for these cookie bars because the metal heats up quickly, and allows the outside of the cookie bars to get golden brown.
- Add some extra M&M’s on top – for some added decoration, place a few M&M’s on top of the dough before baking or press a few on top right after you take the cookie bars out of the oven.
Nutrition
FYI: If you are using a different flour brand than stated DO NOT use the gram calculations. I used Bob’s Redmill Gluten Free All Purpose and it ended up being 18 grams short and my bars never cooked and then fell in the middle.
“2 cup 192 grams brown sugar” Does this mean to use 2 cups AND 192 grams of brown sugar?
Thanks!
No, 2 cups of brown sugar (can also measure in grams, which would be 192 grams). So sorry that wasn’t clear!
Do you think these could be made in a cast iron pan?
We haven’t tried, but I don’t see why not!
These look delicious! I am planning to make them in advance. Do I need to store them in the refrigerator or is the countertop okay? Thank you!
The countertop is fine!!
Use unsalted butter, correct ?
We used salted, but use whatever you have on hand, Allison! Enjoy!
These were so good! I used chocolate chips instead of m&ms. They fell apart on me but still tasted great.
So glad you loved these, Teresa! Thank you for sharing this with us!
I just made these and they are delicious. Definitely good with a scoop of your favorite ice cream. I used all-purpose flower as I have no issues with gluten, but I am sure these are good with gluten free flour too. The recipe is super easy and I didn’t even need to take our my electric mixer.
Aren’t they the best?! Love these and so glad you do too!
These bars or soft and delicious! Such a great treat to bring to a gathering.
Agreed! One of my very favorites! We’re glad you love them!
I have made these at least three times since this recipe was posted. SO good! We love to freeze a bunch after slicing them up so they last longer!
Wahoo! I agree – freezing these is the way to go. Easy treat for when the sweet tooth hits!
I made these today with my son and they’re delicious!! We didn’t have any M&M’s so we used chocolate chips instead. This recipe is a keeper!
I did the same thing when I made these! SO good!!! Thank you for sharing this with us, Katie!
I subbed 1 cup of semi-sweet choco chips because I didn’t have M&M’s in my pantry. This recipe is super easy & super delicious!! The chips did turn out a bit more melted than a M&M would (as the recipe mentioned), but that is alright in my book! I have a feeling this bar recipe will be on my regular treat rotation. Thanks Fed & Fit team!
SO yummy…it’s on my rotation too! We’re so glad you enjoyed this recipe, Kate!
Just made a batch and they are delicious! If I were to double the recipe, do you think I could use a 9×13 pan?
Definitely! They’ll be a little bit thicker, so they may take more time, but you’ll know they’re done when an inserted toothpick comes out clean!
Can recipe be doubled and baked in a 9×13 pan?
Totally! They’ll just be a bit thicker, so they may need a few extra minutes in the oven. You’ll know they’re finished when a toothpick inserted into the middle of the pan comes out clean!
You have both an 8×8 and 9×9 pan listed in both the recipe and the story… which is right? Thanks.
Thanks for catching that! I went ahead and changed the recipe to read 9×9, but either one works great. We’ve made them in both sizes and they’ve turned out perfectly either way! Enjoy!