These super indulgent M&M chocolate chip cookie bars are the ultimate sweet treat! Fudgy brown sugar cookie dough studded with M&M's and M&M chocolate chunks.
Perfect for birthday parties and bake sales, these M&M cookie bars always go down well with a crowd. Best of all they only take 30 minutes to bake, and the hardest part is waiting for them to cool! I know you're going to LOVE them!

We're massive cookie bar fans in this house (don't miss my mini egg cookie bars if you're a fan too), and these M&M cookie bars are always top of the kids request list for birthday parties and after-school treats.
All of the deliciousness of regular M&M cookies without the need to scoop or roll the dough. Just mix, bake, cool, slice, and enjoy!
There are so many different varieties of M&M's you can buy now, have fun experimenting with all the different flavours.
In these bars we used crispy M&M's and chocolate M&M's, as well as an M&M crispy chocolate bar broken into bitesize chunks.
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✔️ Why should you try it?
- Fudgy and delicious
- Great for parties and bake sales
- Can be frozen
- Indulgent sweet treat
- Colourful and bright with the M&M's
🥘 Ingredients

- M&M's - we used a mixture of chocolate M&M's and crispy M&M's.
- M&M's Chocolate Bar - broken up into small chunks. Alternatively, you can use chocolate chips.
- Butter - unsalted butter is best and the butter needs to be melted before use.
- Sugar - a mixture of golden caster sugar and light brown sugar is used, but you can use all light brown sugar for an even fudgier texture.
- Eggs - 2 large free range eggs.
- Vanilla Extract - use a good quality vanilla extract and NOT vanilla essence.
- Flour - plain flour is used because no raising agents are required in this recipe.
🔪 Instructions
The recipe card with ingredient quantities and detailed instructions can be found at the bottom of the post
One: Cream together the melted butter and sugars until they are pale and fluffy.
Two: Beat in the eggs and vanilla extract.
Three: Stir in the flour until it is all combined.
Four: Make sure all the ingredients are thoroughly mixed at this stage.

Five: Add in the M&M's and chocolate chunks (or chocolate chips)
Six: Give the mixture a good stir to combine them into the cookie dough.
Seven: Spoon the mixture into a lined brownie tin or 20cm square baking tin and smooth the top.
Eight: Bake in the oven for 30 minutes. Take out of the oven and push more M&M's into the top of the cookie bars. Allow to cool completely before slicing into bars.

💭 Top tips
- Line your tin (you can use a small brownie tin or a 20cm square baking tin) with baking paper. Make sure you leave the baking paper overhanging the top so that when the cookie bars are cool, you can lift the whole thing out onto a board to cut into bars.
- Add the additional M&M's to the top of the cookie bars after baking to prevent the M&M's burning or the colours running through the cookie dough.
- Speed up cooling time by placing the tin in the fridge (or even freezer!) for 30 minutes to an hour.
- To cut clean neat slices, first make sure the cookie bars are completely cool. Next, lift the cookie bars out of the tin using the overhanging baking paper as handles. Place on a flat wooden board and use a long sharp knife to cut into bars. Clean off the knife carefully between each cut.
🍴 Serving suggestions
These cookie bars are great as a treat with a glass of ice cold milk. They also double up as an easy dessert or pudding, served warm with honeycomb ice cream and drizzled with chocolate fudge sauce!
📖 Variations
- Use different candy combinations. How about smarties or chopped up Mars bars. You could even add mini eggs for an Easter themed cookie bar.
- Make them extra fudgy and rich and replace the caster sugar and light brown sugar with the same quantity of dark brown sugar.
- Add peanut butter chips instead of the chocolate chunks.
- Add a handful of unsalted nuts to the cookie bars for added crunch and texture.

🥡 Storage
The cookie bars can be kept in an airtight container for up to 3 days, making them a great get-ahead treat.
The bars can also be frozen for up to 3 months. Freeze the bars in layers separated by baking paper, in a freezer safe container. Defrost at room temperature before serving.
😋Related recipes
More bars and brownies to try!
- Mini Egg Brownies
- Lemon amd Blueberry Blondies
- Biscoff Tiffin
- Mini Egg Tiffin
- Peanut Butter Swirl Brownies
- Mincemeat Blondies
- Mincemeat Crumble Slices
Tried this recipe? Leave a ⭐⭐⭐⭐⭐ star rating in the comments!
Recipe
M&M Chocolate Chip Cookie Bars
Ingredients
- 200 g Butter melted
- 125 g Golden Caster Sugar or use white caster sugar
- 125 g Light Brown Sugar
- 2 Eggs
- 2 teaspoon Vanilla Extract
- 275 g Plain Flour
- 150 g M&M Chocolate Bar cut into chunks (or use chocolate chips instead)
- 150 g M&M's chocolate ones (or your preference)
Topping
- 50 g M&M's we used crispy M&M's but any flavour is fine.
Instructions
- Preheat the oven to 180°C (160 fan/ 350F/ Gas 4) and line a small brownie pan or 20cm square baking tin with baking paper.
- Cream together the melted butter and sugars in a large mixing bowl until pale and fluffy.
- Beat in the eggs and vanilla extract.
- Stir in the flour until combined.
- Fold in the chocolate chunks and M&M's and spoon the mixture into the prepared tin.
- Bake for 30 minutes (check after 25 minutes as all ovens are different). Take the tin out of the oven and top with the 50g of M&M's (push them into the top very gently so it doesn't crack too much).
- Leave to cool before cutting into bars.
Video
Notes
- Line your tin (you can use a small brownie tin or a 20cm square baking tin) with baking paper. Make sure you leave the baking paper overhanging the top so that when the cookie bars are cool, you can lift the whole thing out onto a board to cut.
- Add the additional M&M's to the top of the cookie bars after baking to prevent the M&M's burning or the colours running through the cookie dough.
- Speed up cooling time by placing the tin into the fridge (or even freezer!) for 30 minutes to an hour.
- To cut clean neat slices, first make sure the cookie bars are completely cool. Next, lift the cookie bars out of the tin using the overhanging baking paper as handles. Place on a flat wooden board and use a long sharp knife to cut into bars. Clean off the knife carefully between each cut.
- Use different candy combinations. How about smarties or chopped up Mars bars. You could even add mini eggs for an Easter themed cookie bar.
- Make them extra fudgy and rich and replace the caster sugar and light brown sugar with the same quantity of dark brown sugar.
- Add peanut butter chips instead of the chocolate chunks.
- Add a handful of unsalted nuts to the cookie bars for added crunch and texture.
Bintu | Budget Delicious
I just know my kids would adore these - and they would definitely find it hard to wait for them to cool! They look so tasty, I can't wait to give them a try.
Adrianne
The melted chocolate in these cookie bars looks simply irresistible! The ingredients sound simple also, what a great recipe, thanks for sharing.
Helen
These look SO good! Makes me wonder why I ever bother rolling dough into cookies! 🙂
Maria
This recipe is so versatile I can easily swap the candies with whatever I'm craving!
Michelle Boule
I made these and shared with my family and we all loved them! Such an easy recipe to make too!
Mirlene
These cookie bars are absolutely amazing! Delicious and just the way I like mine. Yum!
SHANIKA
OMG! I'm loving these M&M Cookie bars! They are such an easy sweet treat for the entire family!
Shashi at SavorySpin
These look so good - perfect to start the week off with!
Beth
This looks amazing and so delicious! Can't wait to give this a try! My family is going to love this!
Dannii
Anything with m&ms is good with me. These cookie bars look amazing.
Sarih
Just made the batter and it is in the oven and looks amazing! Can't wait to taste it! Thanks so much for this awesome recipe!!!
Paula
I just made this one with a chocolate orange - just a whole one smashed up.