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 39 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

105 Comments

  1. 5 stars
    These are a fan favorite in my house! I actually make them for people and give them as gifts. Melting the butter makes such a difference with baked goods. Never in 1 million years would I have thought to do that until I read this recipe and you’re a little brownie bites recipe. Amazing!!!

  2. These are delicious! I have only made them once before but I am making them now to send to my nephew for his birthday. I can’t wait to hear what he thinks after trying them. Also, really easy to make. I did buy the exact 9x9 recommenced pan. I also used Himalayan pink sea salt because that is what I had. These will definitely be a regular baked good in my house.

    1. that would probably work. Cast iron retains heat REALLY well - so they might actually cook a bit faster. Keep your eyes on them for sure

  3. I made these last night for the gift bags I put together for our virtual Xmas party this year and and they are AMAZING! I didn't have a 9x9 pan, but saw another person commented and used an 8x8, I baked for 45 minutes and let them cool for the two hours and they're perfect! So excited to share these!

  4. I have made these twice (following the recipe to a t) and both times the middle has collapsed and still been very gooey! Any suggestions?

  5. Dang it!! I was so excited for these. I made it exactly as recipe calls, baked for 40 minutes in 9x9 metal baking dish and let rest for 2 hours. The edges were crisp but the inside was still so mushy?!?!?! Could it be that we are at 5100 ft elevation? What adjustment should I make.

  6. Just made these using jumbo chocolate chips and chopped pecans - insanely good!! Thanks for such a great base recipe Gaby!

  7. 5 stars
    AMAZING!!! I only had an 8 inch pan, so I baked it for 43 minutes. They turned out fantastic and so easy to put together quickly.

  8. Hi, I hope you're doing well! I'm in NYC and want to bake this while we are sheltering in place. My husband could only find smoked maldon salt at the grocery store (we're so lucky that we even have access to groceries still; so this is really a ridiculous thing to be concerned about on my part). Will smoked maldon taste ok on these? Also, do you recommend salted or unsalted butter?

    1. unsalted butter is best but if you only have salted that's fine too! Just omit the salt from the recipe! And smoked salt might be incredible in this!! You could also just leave it out entirely if you don't want a hint of smoky flavor. Bottom line: it's gonna be good no matter what you do and stay safe! xoxo

4.90 from 39 votes (22 ratings without comment)

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