M&M Cookie Bars

M&M Cookie Bars are the perfect treat for dessert, parties or bake sales! These colorful blondies are sweet and delicious. You're going to want to make this one again and again!

m&m cookie bars on a cooling rack
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A few weeks ago my friend asked for a recipe she could make for a bake sale and I couldn't wait to show her this recipe. M&M cookie bars are the best!

Packed with M&M's and chocolate chips, these colorful blondies are the perfect treat for bake sales, afternoon snacks, taking to a teacher or new neighbor. Who doesn't like M&M's?!

You can even enjoy one of these cookie bars for a special dessert with a scoop of ice cream on top!

Here's why you will love this recipe:

  • It's way easier than cookies because you just have to pour the batter into a pan — you don't have to roll out individual chocolate chip cookies!
  • Made in a 9x13 pan, these cookie bars can be cut into pieces to serve a crowd.
  • The texture is perfectly soft and chewy and the colors are seriously fun. These are great for kids!

This recipe makes 2 dozen cookie bars, which is plenty for a crowd! Make a double batch if you need more or halve the recipe for a smaller amount.

You can also cut them into smaller pieces if you need a larger quantity. Another favorite crowd-pleaser dessert is this Sour Cream Dark Chocolate Pound Cake that everyone loves!

a stack of m&m cookie bars cooling

Ingredients

You will need the basics for this recipe. Here's what to pick up at the grocery store:

  • unsalted butter
  • light brown sugar
  • vanilla extract
  • eggs
  • all-purpose flour
  • salt
  • M&M's
  • chocolate chips

I recommend a nicer flour like King Arthur or White Lily as well as a quality vanilla extract like Nielsen-Massey. These simple hacks will seriously upgrade all your home baking.

Sometimes I sprinkle the tops with flaky sea salt to satisfy my sweet and salty cravings.

If you like, you can also mix in pretzels, potato chips and other flavors of baking chips to play with flavor.

M&M's scattered around a stack of blondies

I usually use plain M&M's but you can use your favorite. Peanut M&M's and Peanut Butter M&M's would both be sooo good. Dark chocolate M&M's would also be so decadent!

You can have fun with color to make these fit into your seasonal entertaining. For example, I always make M&M Christmas Cookie Bars with red & green M&M's at the holidays.

You could use pastel M&M's for Easter and red, white and blue M&M's for July 4. For Halloween cookie bars, use orange and brown M&M's.

Did you know you can buy M&M's colors in bulk? This is a great way to match your cookie bars to a theme for a birthday party, baby shower or bridal shower.

You could even make them in your team's colors for a little team spirit! Great for tailgating or watching the big game at home.

Butter and brown sugar batter being mixed with a whisk.

How to make M&M cookie bars

Making these cookie bars is easier than making chocolate chip cookies or brownies.

If you have ever made blondies (AKA blonde brownies), the process is very similar.

The base is a buttery, brown sugar mix, then flour is gently mixed into the batter in stages.

You can make these by hand with a whisk or go electronic with a stand mixer or hand mixer. There's no wrong way!

Step by step grid of the process of making Christmas M&M cookie bars.

Step By Step Instructions

  1. Preheat the oven to 350ºF and line a 9×13 baking dish with parchment paper.
  2. In a large bowl mix together melted butter, brown sugar and vanilla. Then add in eggs and stir until the batter is like a thick caramel.
  3. In a separate bowl, whisk together flour and salt. Then pour flour into the batter, roughly a ½ cup at a time, folding the batter over itself to smooth any ribbons of flour into the batter. The batter will be very thick.
  4. Add in your M&M's and chocolate chips to batter and gently combine.
  5. Pour into baking pan and spread evenly. Top with additional M&M’s and chocolate chips if desired. Bake at 350ºF for 26 minutes.
  6. Remove parchment paper from pan and set on a cooling rack to cool. You will want to wait to cut them until they have cooled down for at least 30 minutes.
  7. Use a knife or bench scraper to divide into 24 squares.

Hot Tip: I usually cut the edges and corners off of my bars so that I get clean edges on all of my bars, but if you like corner and edge pieces then you can skip this tip!

two boys smiling with m&m cookie bars

Substitutions

Flour: You can make these gluten-free by using a 1:1 gluten-free flour blend instead of all-purpose flour.

Butter: The recipe calls for unsalted butter, but you can use salted butter instead. Just skip the added salt in the recipe.

Sugar: If you'd like to make these refined sugar-free, you can substitute coconut sugar. (I haven't tried with this recipe, but it should work. We do this a lot with baking recipes like my No Sugar Added Blueberry Muffins.)

Can You Make Cookie Bars With Sugar Cookie Mix?

Yes! M&M Sugar Cookie Bars are easy to make with a mix! I am all about a good shortcut sometimes.

First, make your sugar cookie mix according to the package's instructions. At the end, mix in the M&M’s and chocolate chips. Then bake according to package instructions.

M&M Cookie Bar Variations

White chocolate M&M cookie bars: Substitute half or all of the chocolate chips with white chocolate chips. You can even use white chocolate M&M's!

Peanut butter M&M cookie bars: Substitute half the chocolate chips with peanut butter chips. This would be great for the peanut butter & chocolate lovers out there! (No Bake Peanut Butter Bars would also be a big hit, just saying). You could also sprinkle on some cut-up peanut butter cups for a real treat.

Pretzel M&M cookie bars: Add in ½ cup of broken, crumbled pretzels for some sweet and salty flavor. You may wish to sprinkle the top with some sea salt flakes for a little extra crunch and saltiness!

m&m cookie bars on a blue background

Storage tips

After your cookie bars have baked and cooled completely, you can store them in an airtight, food-safe container for up to one week.

To keep them from sticking together, separate layers with wax paper or parchment paper.

m&m blondies cooling on wire racks

If you love cookies as much as we do, you can't ever have enough recipes!

My friend Liz makes these Salted Almond Butter Brownies and they are my absolute favorites. Perfect for another chocolatey bar for your snack table!

These Funfetti Sugar Cookie Bars are a colorful delight — so great for a birthday party.

We also love these Berry Sugar Cookie Bars for the summer holidays.

m&m cookie bars on a blue background

M&M Cookie Bars

Thick, chewy and colorful M&M Cookie Bars will be the a hit at any party or bake sale, and they make a great treat to share with friends and neighbors.
5 from 3 votes
Print Pin Rate
Prep Time: 5 minutes
Cook Time: 25 minutes
Total Time: 30 minutes
Servings: 24 cookie bars
Author: Madison | A Joyfully Mad Kitchen

Ingredients

  • ½ cup unsalted butter melted
  • 2 cups brown sugar packed
  • 2 tablespoons vanilla extract
  • 2 large eggs
  • 2 cups flour
  • ½ teaspoon baking soda
  • 1 teaspoon salt
  • 1 cup plain M&M's
  • 1 cup semi-sweet chocolate chips

Instructions

  • Preheat oven to 350ºF and line a 9x13 baking dish with parchment paper.
  • In a large bowl mix together melted butter, brown sugar and vanilla. Then add in eggs and stir until batter is like a thick caramel.
  • In a separate bowl, whisk together flour, baking soda and salt. Then pour flour into batter, roughly a ½ cup at a time, folding batter over itself to smooth any ribbons of flour into the batter. The batter will be very thick.
  • Add in the M&M's and chocolate chips to batter and gently combine.
  • Pour into baking pan and spread evenly. Top with additional M&M's and chocolate chips if desired. Bake at 350ºF for 26 minutes.
  • Remove parchment paper from pan and set on a cooling rack to cool.
  • Use a knife or bench scraper to divide into 24 squares.

Notes

The cookie bars will be golden brown and firm, but soft and gooey on the inside. You can use a toothpick to see if the cookie bars are completely cooked. A little underdone just makes these cookies extra soft and chewy.

Nutrition

Serving: 1g | Calories: 174kcal | Carbohydrates: 28g | Protein: 2g | Fat: 7g | Saturated Fat: 4g | Polyunsaturated Fat: 2g | Cholesterol: 26mg | Sodium: 126mg | Fiber: 1g | Sugar: 19g

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