Rainbow M&M Cookies

Soft and chewy cookies filled with colorful M&Ms. These are a cookie jar favorite!

Soft and chewy cookies filled with colorful M&Ms. These are absolutely a cookie jar favorite!

These incredibly addicting cookies are super chewy and, by far, the softest cookie I’ve ever baked.  They completely disappeared when I brought them into work, with some people even asking me if they were store-bought.  Store-bought? The horror!

I adapted the recipe from the famous Cooks Illustrated Chewy Chocolate Chip Cookie.

Rather than melting the butter – as directed in the Cooks Illustrated recipe – I creamed the butter with the sugars and eggs, which produced an exceptionally thick and puffy cookie.  Just the way I like them!   Another trick to get a thick and puffy cookie is to chill the dough.  Like, for hours.  Yup… 30 minutes and to up to 5 days of chilling.

Soft and chewy cookies filled with colorful M&Ms. These are a cookie jar favorite!

The unbelievably soft texture and chewiness to this cookie can be attributed to the extra egg yolk.   Egg yolks are the source behind a cookies soft texture.  This recipe calls for 1 whole egg and 1 egg yolk.  Also credited to the chewiness of this cookie is the brown sugar to white sugar ratio.  This recipe calls for double the amount of brown sugar to white.  So, with double egg yolks and double brown sugar, these babies have double the softness and double the chewy texture!

Make these amazing cookies now and learn why you will use this recipe time and time again!

Rainbow M&M Cookies

Soft and chewy cookies filled with colorful M&Ms. These are a cookie jar favorite!


  • 2 cups + 2 tablespoons all-purpose flour
  • 1/2 teaspoons baking soda
  • 1/2 teaspoon salt
  • 3/4 cup (1.5 sticks) unsalted butter, softened to room temperature
  • 1 cup packed light brown sugar
  • 1/2 cup granulated sugar
  • 1 large egg, at room temperature
  • 1 large egg yolk, at room temperature
  • 2 teaspoons pure vanilla extract
  • 1 cup mini M&Ms


  1. Whisk the flour, baking soda, and salt together in a large bowl. Set aside.
  2. In large bowl using a hand-held mixer or stand mixer fitted with a paddle attachment, beat softened butter for about 1 minute on medium speed until creamy. Add the brown sugar and granulated sugar, then beat on medium-high speed until creamy and combined. Scrape down the sides and bottom of the bowl as needed. Beat in egg, egg yolk, and vanilla extract. Scrape down the sides and bottom of the bowl as needed. With the mixer running on low speed, slowly add dry ingredients to wet ingredients. Pour in the M&Ms and beat on low speed for 20 seconds or until combined. Once completely combined, cover cookie dough tightly and chill in the refrigerator for 30 minutes and up to 5 days.
  3. Preheat the oven to 325°F (163°C). Line a large baking sheet with parchment paper or a silicone baking mat. Set aside.
  4. Remove cookie dough from the refrigerator. Drop by Tablespoonfuls onto prepared baking sheet. Bake for 8-10 minutes or until edges are slightly browned. The centers should appear very soft and puffy. If desired, press a few mini M&Ms into the tops of the warm cookies for looks. Repeat with remaining cookie dough.
  5. Make ahead tip: Cookies stay fresh covered at room temperature for up to 1 week. You can make the cookie dough and chill it in the refrigerator for up to 5 days. Allow to come to room temperature and continue with step 4. Baked cookies freeze well for up to 3 months. Unbaked cookie dough balls freeze well for up to 3 months. Bake frozen cookie dough balls for an extra minute, no need to thaw. Click here for my tips and tricks on freezing cookie dough.

Recipe Notes:

Make sure to keep dough cold at all times while the batches are baking. I keep my dough in the refrigerator in between batches. You can easily swap add more add-ins to these cookies (chopped candy bars, nuts, chocolate chips, etc) as long as the total does not go over 1 cup. Get creative!

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© Sally’s Baking Addiction. All images & content are copyright protected. Please do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words, or link back to this post for the recipe.


Check out some of my other favorite homemade cookie recipes.

Like these Peanut Butter Cup Oatmeal Cookies 

Peanut Butter Cup Oatmeal Cookies-4


And these Sweet & Salty Potato Chip Toffee Cookies.

Potato Chip Toffee Cookies by Sallys Baking Addiction






  1. Hi.. Is it possible to make it as a cake size?
    Like giant?

  2. Hi Sally! I LOVE your blog and have had great luck with everything. Just wondering–is there a reason why you use salted butter in this recipe?

    Thanks so much,

    • Hi Betsy! I actually prefer salted butter in most of my cookie recipes, but write them with unsalted butter since that is what most people use anyway. I like the slight increase in saltiness. You may use unsalted here, without changing anything else about the recipe.

  3. I just made these with my daughter-her request…m&m cookies, but NOT monster cookies. We were just tasting the dough, when it dawned on me…there is no salt in the recipe! Yikes…I like salty with my sweet. BUUUUUT, I will try them as is for the first batch, then sprinkle salt on top if I need to. Chilling as we speak, I’ll let ya know!

    • Oh.my.gosh! I JUST noticed the comment above mine, and did not realize the recipe called for salted butter. Great. This is why I can’t bake. I’ll cook any day and all day, but baking—just not enough wiggle room for me!

  4. I made these for my son’s preschool class…so yummy! Incredibly sweet, and moist. Love your blog..you are incredibly talented! Thank you for sharing :)!

  5. This recipe sounds sooo good, but is it possible to cut the recipe in half. I would like to put them in mason jars that I have for a shower favor (quart size) but it’s just difficult to fit it all in the jar. All the ingredients seem simple enough to cut in half…but the egg is the problem. Any suggestions. Thank you

  6. i LOVED the dough, but had to increase baking time by 7 minutes at 325, and they were still a bit undercooked for my taste. I increased the temp to 350 (using convection setting this time), but still required baking for 12 minutes. The final product was wonderful, though! The recipe is a keeper with the changes I mentioned, thanks!

  7. Hi, Sally!

    I have a question about these delicious cookies.
    I’m making a “cookie cake” for my son’s birthday, and was wondering if the large cookie would turn out as well as the individual small ones. We’ve made these before, and LOVED them, but I was just wondering if it’d work on a larger scale.

  8. Hi was just wondering is it OK to use xlg eggs for this recipe that is all I have? Or would that change things?

  9. Hi Sally! Anytime I try this recipe, something goes wrong. Either my dough does not form and becomes crumbly, or my cookies are as flat as pancakes. Any idea on what I could be doing wrong? Thanks in advance!

    • Karina, are you changing anything about the recipe at all? Make sure you are measuring your flour correctly (spoon and level) and chilling the dough. Do you bake cookies on a silicone baking mat? (Such as Silpat)– I find my batches of cookies bake wonderfully each time using one.

  10. Mine are taking forever to cook! About 12-13 minutes and the centers are still ‘gooey’. Should I turn it to 350 next time?

  11. Please could you provide the numger of grams of m&ms needed? I also can only find the normal sized m&ms in the UK – will that suffice?


  12. Hi Sally,
    How long should I leave the eggs and butter out for? Looking forward to trying these!

    • Until room temperature – I’d say at least an hour. For the egg, set it in a glass of warm water for 10 minutes.

  13. Hi, 
    The M&M’s melt and get weird coloring everywhere, please help?

  14. Hello,
    Could I make this recipe with peanut m&ms?
    I have been having difficulty finding a peanut m&m cookie that doesn’t involve a peanut butter cookie base. 

  15. So I literally just combined the ingredients to these Rainbow M&M Cookies and put them in the fridge to chill. It wasn’t until after I combined everything that I read that the add-ins should not exceed one cup. I’m making blue and yellow m&m cookies for a baby shower and it didn’t look colorful enough so I added extra m&m’s, about an additional half cup extra. Is that going to hurt the look/taste of the cookie? I’m baking them tomorrow evening. Baby shower is Saturday the 23rd. 

  16. Baking these on a humid day, so having some spreading issues. Sally, how do you combat humidity? Also, I’m seeing some people referencing cornstarch, but I don’t see this in the recipe…

    • Hi Jenn! I use cornstarch in a lot of my cookie recipes (after posting this one back in 2012), so you can add a teaspoon to this cookie dough if you’d like. Just makes the cookies a little softer. On super humid days, sometimes I add 1-2 more Tablespoons of flour and chill the cookie dough for at least 1 full day in the refrigerator.

      • Thanks, Sally! I receive so many compliments when I bake from your recipes. I love that I’ve learned so many techniques from you (dough chilling and cookie towers for baking have been a game changer!).

  17. Made these with s’more m&m’s today – super delicious!  Thanks Sally!

  18. Hi Sally!
    I was wondering if you could share the recipes in grams? 🙂 
    I’d be highly grateful!

    Thank you!

    P.S. Your recipes are amazing! 😀

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