Preppy Kitchen Recipes Desserts Brownies & Bars M&M Cookie Bars

M&M Cookie Bars

Name: M&M Cookie Bars Recipe
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Ingredients: 2⅔ cups all-purpose flour ((320g)); ½ teaspoon baking soda; ½ teaspoon baking powder; ¾ teaspoon salt; 1 cup unsalted butter (softened (226g)); 1 cup packed light brown sugar ((220g)); ½ cup granulated sugar ((100g)); 2 large eggs; 2½ teaspoons vanilla extract; 1 cup regular M&Ms (plus more for sprinkling (220g)); ½ cup semisweet chocolate chips (plus more for sprinkling (90g))

By John Kanell Published Dec 6, 2024
Add a comment
Jump to Recipe

This post may contain affiliate links. Please read our disclosure policy.

My chewy M&M Cookie Bars feature crisp edges, a rainbow of chocolate candies, and a chewy blondie-like center. Better yet, these festive treats are made in a single batch in just one pan—it’s a favorite easy recipe for Christmas cookies!

Two pieces of M&M cookie bars on a plate with a platter of more and a glass of milk in the background.

Rather than choose bars OR cookies, why not have both at the same time with these easy M&M cookie bars? These candy-studded cookie bars are so easy to make and turn out perfectly every time.

But don’t let their simplicity fool you. Between a base that texturally lands somewhere between chocolate chip cookies and blondies and a double dose of chocolate from M&M candies and chocolate chips, these little beauties are sure to please. Plus, they’re easy to customize for any occasion—just pick up whichever candy colors you wish for the season! For more cookie bar recipes, try my gingerbread bars, sugar cookie bars, and brookies.

Ingredients

All-purpose flour — plain white flour is all you need! Make sure to use either a kitchen scale or the fluff, spoon, and sweep method to ensure your dry-to-wet ingredient ratio is correct.

Baking soda & baking powder — we’ll need both leaveners to make these bar cookies chewy with just the right density.

Salt & unsalted butter — I almost always bake with unsalted butter, then add salt to taste.

Light brown sugar & granulated sugar — brown sugar’s molasses content helps these chewy cookie bars stay moist. Granulated white sugar, on the other hand, is what helps achieve that crackly top and crisp edges. If needed, swap in cane sugar for granulated or make your own brown sugar using white sugar and molasses.

Large eggs — let them come to room temperature before starting to make them easier to incorporate. Just pull them out of the fridge about 30 minutes in advance of your bake session.

Vanilla extract — make sure to use the real deal; the bottle should say “pure” vanilla extract.

M&M candies — use the classic mix or flavor or customize your colors based on your theme or holiday.

Semisweet chocolate chips — the higher cacao content of semisweet chocolate provides a nice balance to the sweet milk chocolate candies. Feel free to swap in mini chocolate chips if you like!

Set of two photos showing dry ingredients whisked and sugars added to butter.

1. Preheat the oven to 350°F. Grease a 9×13-inch baking pan with baking spray and line with parchment paper. In a medium bowl, whisk together the dry ingredients—flour, baking soda, and salt. Set aside.

2. In a large bowl, using a hand mixer or a stand mixer with the paddle attachment, beat the butter and sugars on medium speed until smooth and well combined, about 2 minutes. (If it’s too fluffy, the bars will be crumbly, not chewy.)

Set of two photos showing eggs and flour added to a mixer.

3. Add the egg and vanilla, and beat until well combined, stopping to scrape down the sides of the bowl as needed.

4. With the mixer running on low speed, add the flour mixture and beat just until combined. Fold in the M&Ms and chocolate chips.

Set of two photos showing chocolate chips and M&M's added to the batter and spread into a lined baking dish.

5. Transfer the cookie dough to the prepared pan and press it into an even layer.

6. Sprinkle the top with more M&Ms and chocolate chips if desired. Bake for 20 to 25 minutes or until the cookie dough is lightly browned and appears dry and slightly shiny on the surface with a warm golden brown hue. Let cool completely in the pan on a wire rack. Use the parchment to remove the cookie slab from the pan and cut it into bars.

Overhead view of an uncut slab of M&M cookie bars on a wooden serving board. M&M's and a linen napkin on the side.

Can I Use Brown Butter?

Yes! Browned butter adds a lovely nutty richness. Just follow my guide on how to get it to the right consistency for using in place of softened butter.

Variations

Use other types of M&Ms: You have lots of ways to customize with different color mixes for different holiday (Halloween, Fourth of July, Christmas). You can also use other flavors of M&Ms like peanut or almond, peanut butter, dark chocolate, crunchy cookie, or holiday mint chocolate. Feel free to experiment!
Add sprinkles: Amp up the festivity by stirring in ½ cup of your favorite sprinkles to the batter and then sprinkle a few more on top before baking.
Top with frosting: Spread vanilla buttercream, chocolate buttercream, or your favorite flavor on top of the cooled bars before cutting.

A green plate with two pieces of M&M cookie bars with a glass of milk in the back.

Can I Scoop The Dough Into Round Cookies?

I don’t recommend it. Instead, make my M&M Cookies recipe if you want individual cookies!

How To Store

Room temperature: Allow the cookie bars to cool completely before transferring them to any kind of airtight container or zip-top bag. They’ll keep well at room temperature for about 5 days. You can slightly extend this shelf life by storing them in the fridge for up to a week.

Freezer: Whether you freeze them uncut or have already portioned them, I recommend wrapping the slab or individual bar cookies with plastic wrap before placing them in a freezer-safe bag. For maximum protection against freezer burn, remove as much air as possible. They should keep well for up to 3 months. To serve, simply allow them to defrost for an hour at room temperature!

Pro Tips For Making This Recipe

Use the right pan. For this M&M’s cookie bar recipe, you should use a 9×13″ metal pan, not a rimmed baking sheet—using the latter causes a crater in the middle of the pan.
For easy removal, make a parchment sling. Lay a long piece of parchment paper in the baking pan, making sure there is a good amount (about 2 inches) of overhang on each long side of the pan. Once your bars are done baking and cooled, simply lift the spare paper to remove the whole slab for cutting.
Get creative! A haphazard sprinkling of bright candy has its charm, but M&M’s are like round Legos—you can use them to spell out a phrase, decorate with a big number or letter, or draw a picture!

A piece of M&M cookie bar on a marble surface. More on the side.

Frequently Asked Questions

How do I cut the bars cleanly?

I recommend chilling the M&M bars for an hour before slicing. This will firm them up for much cleaner cuts. Be sure to use a sharp knife, too!

Do I have to use M&Ms?

Nope! Trade them for Reese’s pieces or other coated chocolate candies, or chop up candy bars into small pieces. You could even add nuts and/or dried fruits.

Can I make the dough ahead of time before baking it?

Yes! Press it into the pan, cover well, and chill in the fridge for up to 72 hours. Uncover and bake as directed directly from the fridge, but note that the bake time will increase by a couple of minutes.

Planning ahead? Freeze cookie dough tray whole for up to 2 months, wrapped tightly in several layers of plastic wrap. To bake, allow to defrost overnight in the fridge, unwrap, and proceed with the baking as instructed, adding a few extra minutes to the bake time as needed.

If you’ve tried this M&M Cookie Bars recipe, then don’t forget to rate it and let me know how you got on in the comments below. I love hearing from you!