M&M Chocolate Chip Cookie Bars

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Quick, easy, and so delicious. These homemade M&M chocolate chip cookie bars are super soft & chewy, full of chocolate, and ready in less than 45 minutes!

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I’ve been on quite the cookie bar kick. I mean, what’s not to love about them?! One of the easiest homemade desserts to make, you can never have too many go-to cookie bar recipes, in my opinion.

I recently posted these Brown Butter Chocolate Chip Cookie Bars and I’ve been obsessed. Then, I decided that I needed to revisit my recipe for M&M Chocolate Chip Cookie Bars that I posted on Instagram a little while ago. I made a few tweaks to the amount of dry ingredients and I’m very happy with how they turned out.

They’re still super soft and chewy and full of chocolate. But, in comparison to my Brown Butter Chocolate Chip Cookie Bars, they’re a little bit thicker, fluffier, and have more of a cake-like texture. I’ve been taste testing them over the past few days to ensure that they keep this texture and I’m happy to report that they do. So, now, you just need to decide: do you want a corner or a middle piece?

Read on for the full recipe for these perfect M&M Chocolate Chip Cookie Bars.

A good, classic cookie bar recipe is a staple for every baker. You never know when you’re going to need to make a delicious, last-minute dessert. The two best things about cookie bars are: 1) you get a high yield in such a short amount of time and 2) there are very few dishes.

For this recipe, I wanted to keep everything nice and simple because that’s the whole point of cookie bars. They’re supposed to be stress free. So, I decided to use melted butter for the base for our dough as that eliminates the need for a mixer. Literally, all you need is one bowl.

A few tips for success:

1. After melting your butter, let it cool for 10 minutes before whisking it with the sugars. You never want to use extremely hot butter when baking cookies and cookie bars. It will impact how the ingredients combine together and will therefore affect the way your cookies and cookie bars bake up.
2. Make sure your egg and egg yolk are at room temperature. I will admit, I don’t always set them out far enough in advance. But, if the eggs still feel cold to the touch, I will run them under some lukewarm water just to warm them up a little bit.
3. Do not overbake your cookie bars. A major reason as to why cookies and cookie bars end up dry and crumbly is often because they’re overbaked. Your cookie bars will continue to bake and set in the hot pan even after they’re removed from the oven. Use the bake time listed in this recipe as a guide — instead, prioritize these two things to conclude if your cookie bars are done baking: 1) the cookie bars should be a light golden color. The edges should be set and may be a bit darker in color than the center and 2) the toothpick test! Insert a toothpick into the center of your cookie bars. If it comes out clean or with a few moist crumbs, remove the cookie bars from the oven.

This really is a short, sweet, and simple recipe — and that’s the way a cookie bar recipe should be!

Other M&M recipes you may like:

• Mini Chocolate Dipped M&M Chocolate Chip Cookies
• Cheesecake Stuffed M&M Oreo Cookies
• Chocolate Frosted M&M Brownies
• Easy Chocolate Dipped Peanut Butter Stuffed M&M Cookies
• The Best Brown Butter M&M Chocolate Chip Cookies
• Nutella Stuffed M&M Cookies

Ingredients you’ll need:

• Unsalted butter
• Granulated sugar
• Brown sugar
• Eggs
• Vanilla extract
• All-purpose flour
• Baking soda
• Salt
• Semisweet chocolate chips
• Mini semisweet chocolate chips
• Mini M&Ms
• Flaky sea salt

Kitchen tools you’ll need (linking my favorites below!)

• Mixing bowls
• Measuring cups
• Spatula
• Whisk
• 8 inch square baking pan
• Parchment paper

How to make these dreamy M&M Chocolate Chip Cookie Bars

Preheat the oven to 350 degrees Fahrenheit. Line an 8 inch square baking pan with parchment paper and spray with nonstick cooking spray. Set aside.

Melt 10 tbsp unsalted butter. Set aside to cool for 10 minutes.

Whisk the dry ingredients in a medium-sized bowl: 1⅔ cups all-purpose flour, 1½ tsp baking soda, and ¼ tsp salt. Set aside.

In a large bowl, whisk together ¼ cup granulated sugar, ¾ cup brown sugar, and the melted butter. Whisk until the mixture is smooth and the ingredients are fully combined.

Add the egg, egg yolk, and 2 tsp vanilla extract. Whisk again until smooth.

Add the dry ingredients to the wet ingredients. Fold in with a rubber spatula until a few flour streaks remain. Gently fold in the toppings: ½ cup semisweet chocolate chips, ½ cup mini semisweet chocolate chips, and ½ cup mini M&Ms.

Spread the cookie dough, creating an even layer in the prepared baking pan. If desired, add extra toppings and press in lightly with the back of a spoon.

Place the pan in the oven and bake for about 22-25 minutes. I recommend checking your cookie bars, starting at the 18-minute mark. The cookie bars are done baking when they are lightly golden on top and set. You can also do a toothpick test. Insert a toothpick into the bars — if it comes out clean or with a few crumbs, they are done baking.

Take the cookie bars out of the oven, top with flaky sea salt, and let them cool for 30 minutes to 1 hour before slicing.

Store in an airtight container at room temperature for up to 5 days or freeze for up to 3 months.

Tips for success

• When measuring dry ingredients, use a kitchen scale or the spoon and level method. While it is more accurate to measure dry ingredients by weight (grams), I bake using volume measurements (cups). This recipe can easily be converted using an online conversion calculator, like this one from Inch Calculator. For the spoon and level method, before scooping out dry ingredients, use a spoon and run through them, fluffing them up and removing any clumps. Then, spoon the ingredient into the measuring cup and use a flat top tool to level off the top and remove any excess.
• Do not overmix your cookie dough and do not overbake your cookie bars! These are the two leading culprits that will cause your cookie bars to be dry and crumbly and we do not want that! Gently fold in your dry ingredients until just a few flour streaks remain. Then, fold in your toppings. By the time your toppings are fully incorporated, there shouldn’t be any flour streaks remaining. As far as overbaking goes, use the bake time listed as a guide! Remove your cookie bars from the oven when the edges are set and the cookie bars are golden in color. If a toothpick inserted in the middle comes out clean or with a few crumbs, they’re done baking.
• Let the cookie bars cool completely before slicing. I usually let mine sit and set for at least an hour.

FAQs

Can I double this recipe?

Absolutely! You will just need to double the ingredients and use a 9×13-inch pan instead. The baking temperature will remain the same, but bake time may vary. Set your timer for 18 minutes and check on the cookie bars every 1-2 minutes.

Can I freeze these cookie bars?

Yep — that’s what I always do with all of my extra baked goods. Store them in the freezer in a freezer-safe storage bag or container. Take them out about 30 minutes to 1 hour prior to consuming. You can also pop them in the microwave for about 10-15 seconds to warm them up and make them all nice and gooey.

Can I substitute with other toppings?

Of course! With this recipe, the most important part is getting the dough itself right. The toppings/add-ins can easily be substituted. My recommendation is to keep the total amount of toppings to 1½ cups. If you want to add more toppings, I would recommend waiting until you’ve placed the dough into the baking pan. Then, you can sprinkle any additional toppings on top right before baking.

How to store

Store the cookie bars in an airtight container at room temperature for up to 5 days or freeze for up to 3 months. If freezing, store the sliced cookie bars in a freezer-safe storage bag or container. Set the cookie bars out and let them come to room temperature before eating them.

A classic, easy cookie bar recipe that everyone will love! They’re soft and chewy, loaded with chocolate, and ready in less than 45 minutes. What could be better?!

If you try this recipe, share and tag me on socials using @itsbrunchoklock or #itsbrunchoklock.