M&M Cookie Bars

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M&M Cookie Bars!! One of my favorite desserts of all times. And also be warned - one is NOT to be left alone with a pan of these! These cookie bars are on par with my famous cheesecake cookie bars. You may want to check those out as well!

An overhead shot of 16 square Christmas MM Cookie Bars


 

Why I Love This Recipe

Is there anything better than a soft cookie in bar form? Where the edges are just lightly golden brown and a tad bit crunchy... and the inside is gooey and soft and melts in your mouth? Let me answer that for you.... no.

It doesn't get better than cookie bars when it comes to a quick and easy dessert that literally every single person will love. These cookie bars are my favorite sugar cookie recipe baked up in bar form. You all know how I love the giant M&M cookies and these are just the perfect bar form for that perfect cookie!

Ingredients & Substitutions

Mise-en-place with all the ingredients to make m&m cookie bars
  • Butter
  • Light Brown Sugar
  • Vanilla Extract
  • Large Eggs
  • All Purpose Flour
  • Baking Powder
  • Baking Soda
  • Christmas M&M’s
  • Maldon

*For a full list of ingredients and instructions please see recipe card below.

A glass mixing bowl with melted butter and brown sugar.

Step 1: Preheat the oven to 350 degrees. In a large bowl, combine the melted butter and brown sugar and mix with a wooden spoon for 1 minute until combined.

A glass mixing bowl with a mix of melted butter and sugar, with two eggs added but not mixed in yet.

Step 2: Add the vanilla and eggs, making sure to scrape down the sides of the bowl, and mix until fully incorporated.

A glass mixing bowl with wet ingredients and dry ingredients just added.

Step 3: Add the dry ingredients into the bowl and slowly mix until just combined. The batter will be a bit stiff, but that's normal.

A glass mixing bowl with M&M cookie batter with red and green M&Ms just added.

Step 4: Fold in 1 cup of the Milk Chocolate M&M’s.

A square baking pan with M&M cookie batter and topped with red and green M&Ms.

Step 5: Spray a 9x9 metal baking pan (see note above) with baking spray and line it with parchment paper. Spoon the batter into the prepared baking sheet and sprinkle with the remaining Milk Chocolate M&M’s and Maldon sea salt if desired.

A square baking pan with M&M cookie square baked in it.

Step 6: Transfer it into the oven. Bake for 35-40 minutes. Once the bars have baked, remove them from the oven and let cool for at least 2 hours before cutting and serving.

Cut these into squares once cooled, and store in an airtight container for a few days. You can also store in the fridge to keep them longer, about two weeks.

We have not had leftovers for these in our household! However, if you want to freeze them, store these bars in a freezer bag or airtight container for about 3 months. Defrost in the fridge or outside to serve.

Tips & Tricks

1: Use a 9x9 pan. Don't try and do it in a 9x13 or an 8x8... it won't be the same. Trust me - there's a reason I developed it this way! And a glass or ceramic baking dish doesn't retain heat the same way a metal baking dish does... so use a metal baking dish! And 8x8 (while it's the same shape is only 64 square inches and a 9x9 is 81 inches. So that will WILDLY affect baking time.

2: Don't skimp on the M&M's and the sprinkle of salt on top. It really makes all the flavors sing! If you want to add more M&M's mid bake, that will ensure they don't fall to the bottom of the pan.

3: After the baking time - LET THESE SET FOR 2 HOURS. These cookie bars might look a little under-baked but they need time to finish residual baking once they come out of the oven.

4: Proceed with caution once these cookie bars are baked and cut. I've eaten pretty much an entire pan once before and I'm not even remotely exaggerating. Thomas had to remove the last 2 squares from the house because I could NOT BE STOPPED.

A glass bowl with red and green M&Ms with some M&Ms outside the bowl on the counter.

FAQs

What is the difference between cookies and cookie bars?

Cookie bars are somewhere cakes and cookies. A great and easy way to make a big batch, and the thickness gives them a nice gooeyness. While not all cookie recipes may be suitable for cookie bars, this is a great one! Thickness is also important when baking bars, too thin and it will be too crisp, too thick and the edges will be brittle by the time the center bakes.

Can I add other things to these cookie bars?

Yes! Add nuts, pretzel, chocolate chips- all perfect additions to these bars.

Similar Recipes

If you tried this recipe, please leave a 🌟 star rating and let me know how it goes in the 📝 comments below. Thanks for visiting today

Soft Sugar M&M Cookie Bars

Author: Gaby Dalkin
4.9 from 38 votes
M&M Cookie Bars!! One of my favorite desserts of all times. And also be warned – one is NOT to be left alone with a pan of these!
Prep Time 5 minutes
Cook Time 40 minutes
Total Time 45 minutes
Course Dessert
Cuisine American
Servings 16 bars

Ingredients
  

  • 1 cup butter melted
  • 2 cup light brown sugar
  • 4 teaspoons vanilla extract
  • 2 large eggs
  • 2 cups all purpose flour
  • 1 teaspoon baking powder
  • ¼ teaspoon of baking soda
  • 1 cup Milk Chocolate M&M’s plus extra for garnish
  • Maldon sea salt optional

Instructions
 

  • Preheat oven to 350 degrees.
  • In a large bowl, combine the melted butter and brown sugar and mix with a wooden spoon for 1 minute until combined. Add the vanilla and eggs, making sure to scrape down the sides of the bowl, and mix until fully incorporated.
  • Add the dry ingredients into the bowl and slowly mix until just combined. The batter will be a bit stiff, but that's normal. Fold in 1 cup of the Milk Chocolate M&M’s.
  • Spray a 9x9 metal baking pan (see note above) with baking spray and line it with parchment paper. Spoon the batter into the prepared baking sheet and sprinkle with the remaining Milk Chocolate M&M’s and Maldon sea salt if desired and transfer it into the oven. Bake for 35-40 minutes. Once the bars have baked, remove them from the oven and let cool for at least 2 hours before cutting and serving.

Notes

  • Use a 9×9 pan. Don’t try and do it in a 9×13 or an 8×8… it won’t be the same. Trust me – there’s a reason I developed it this way! And a glass baking dish doesn’t retain heat the same way a metal baking dish does… so use a metal baking dish!
  • Don’t skimp on the M&M’s and the sprinkle of salt on top. It really makes all the flavors sing! If you want to add more M&M’s mid bake, that will ensure they don’t fall to the bottom of the pan.
  • After the baking time – LET THESE SET FOR 2 HOURS. They might look a little under-baked but they need time to finish residual baking once they come out of the oven.

Nutrition Information

Calories: 339kcal | Carbohydrates: 48g | Protein: 3g | Fat: 15g | Saturated Fat: 9g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.5g | Cholesterol: 53mg | Sodium: 160mg | Potassium: 66mg | Fiber: 1g | Sugar: 35g | Vitamin A: 414IU | Vitamin C: 0.1mg | Calcium: 62mg | Iron: 1mg
Tried this Recipe? Tag me Today!Mention @WhatsGabyCookin or tag #whatsgabycooking!

Photography by Matt Armendariz / Food Styling by Adam Pearson

102 Comments

  1. 5 stars
    I’ve made this recipe three times, with perfection each time, following the recipe as written. It’s my new quick, all around, crowd-pleasing favorite! This week I’ll try it with chocolate chips… thoughts?
    Thank you again for all your recipes 🙂

  2. I have made these 4 times now, with the same result. Overbaked on the outside and gooey almost raw center. I even purchased the pan you recommended and temperature gauge for my oven. What could the issue be?

  3. If I do 1 ½ times the recipe, can I bake it in a 9x13 like you said you did in the video? If so, how long did you bake?

    1. you can but the middle will be gooey. 9x13 is a tough size for this recipe bc the center takes longer to bake and the edges get a little over done

      If you needed a double batch, I'd just do 2 9x9 pans to be extra safe

  4. 4 stars
    Very tasty, but I am surprised that there is no salt called out in the ingredients (I added a little over a teaspoon of diamond kosher and definitely would add again next time). Also, next time I will not be spraying my pans - my cookies came out a little bit greasy on the bottom/sides, and I think there's enough butter that it wouldn't have stuck without spray. Alternatively, I might try using parchment paper instead of spray next time. Lastly - I didn't have a 9x9 pan, so I used a 8x8 pan and a mini loaf pan and it worked out great. The bars did seem underdone when I took them out of the oven, but they cooled/set to perfection.

    1. Hey Brogan! There is salt mentioned - on top! Maldon 🙂 But totally down for you to add salt to the batter. Parchment paper works great too as I mention in the directions 🙂

  5. I followed the recipe exactly except I did not have a 9x9 metal pan so I divided the batter into 2 8x8 metal pans and baked for 30 minutes, cooled for 1 hour and they were perfect! The family devoured them!

  6. Would love to know if you’ve you’ve ever heard of anyone experimenting (and seeing success) with gluten free flour. I use the standard 1-to-1 gluten free flour. Made some modifications to your Christmas mix last week and it was a big hit!

  7. I am letting mine cool now. Definitely soft in the middle. I hope they set up after they cool.
    Gaby, do you ever do weights for measurements?

  8. 5 stars
    Deliciousness! For Pete’s sake, read the note about pan size, still grabbed the wrong one and used 8 x 8. Had to Cook longer. Middle too soft. Use the 9 x 9! Couldn’t use for cookie exchange as planned but kept for ourselves….darn. Will definitely make again and use the correct pan.

  9. Any recommendations for storing and how long they last? Making for Holiday gifts but not sure how far in advance they are OK make to keep safe until gifting. Will be individually bagging.

    Also my m&ms did not stay on top so they don't look pretty from above. Any recommendations on how to get them not to sink in batter?

  10. Am I reading correctly, no salt in the recipe itself? I made as written and feel like they're missing a depth of flavor ... possibly because there's no salt in the recipe, except for the optional sprinkling on top??

  11. Your recipe calls for 2 eggs but your video shows 3 eggs. Looks like you used a 9x9 pan. Can you explain please? Thank you.

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