Christmas M&M Cookie Bars

Name: Christmas M&M Cookie Bars
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Ingredients: 150 g Softened butter ((1+⅓ sticks)); 130 g Caster sugar ((⅔ cup)); 100 g Soft light brown sugar ((½ cup)); 1 Medium Egg; 1 Teaspoon Vanilla extract; 250 g Self-raising flour ((2 cups)); 100 g Mini red and green M&Ms ((½ cup) I bought 2 bags and picked out the green and red ones); 25 g Milk chocolate chips ((2 tablespoons)); 25 g White chocolate chips ((2 tablespoons))

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These Christmas M&M cookie bars make a delicious treat for holiday gatherings or edible gifting. They’re soft and chewy, packed with green and red M&Ms and two types of chocolate chips.

4 M and M Christmas cookie bars on a plate

If you’re looking for a quick and festive dessert that is suitable for both kids and adults, these Christmas M&M cookie bars are just the thing! They’re easy to make in one pan so there’s no shaping or cutting out required, making them ideal for last-minute party desserts or school bake sales.

For all my beginner bakers out there, I've written everything you need to know in the post below. This includes ingredient and equipment notes, top tips and a couple of step-by-step photos. I hope you find it helpful! And for those who are more advanced in the kitchen, you can find the short, bullet-pointed version in the recipe card at the end of the post. Enjoy!

Ingredients

Here's everything you'll need to make these M&M Christmas cookie bars...

Butter: Use softened butter to make it easier to mix. You can either leave it at room temperature for an hour before you start baking or you can pop it into the microwave for 10 seconds. I personally think salted butter tastes best with the sweetness of the mix-ins but if you only have unsalted butter, you can just add a small pinch of salt separately when mixing your ingredients.
Sugar: A mix of white sugar and brown sugar works best for this recipe. The white sugar helps create a slightly crisp top, while the brown sugar gives the cookies a soft caramel-ly chew. I like to use caster sugar and soft light brown sugar.
Egg: 1 medium egg, to help the ingredients bind together.
Vanilla extract: This flavouring pairs perfectly with the chocolate chips and M&Ms but if you fancy something even more festive, you can swap it out for orange or peppermint extract.
Self-raising flour: Self-raising flour will give the bars a slight lift while still maintaining a dense, chewy texture. If you only have plain flour to hand, you can substitute it by adding 1½ teaspoons of baking powder and a small pinch of salt.
Mini M&Ms: I bought two bags of mini M&Ms and picked 100g of green and red ones out (50g or ¼ cup of each colour).
Chocolate chips: I used a mixture of milk and white chocolate chips but feel free to use whichever kind you like best. Even dark chocolate chips would taste great in this recipe.

Kitchen Equipment

Mixing bowl: A large one for mixing the dough ingredients together.
Utensils: You'll need a wooden spoon and a teaspoon. If you're finding it tricky to mix the butter and sugar together, you can also use an electric hand whisk or stand mixer to help you along.
Baking tin: I used an 8x10-inch tin in the process photos but you can make this recipe in an 8x8-inch tin if you want slightly thicker Christmas cookie bars.
Baking paper: To prevent the cookie from sticking. I also used an additional piece to help me smoothly press the dough into the tin.

overhead image of christmas M&M cookie bars

How To Make Christmas M&M Cookie Bars

Step 1: Start by preheating your oven to 180°C/325°F (or 160°C/325°F if you're using a fan or convection oven). Then line an 8x10-inch or 8x8-inch tin with baking paper with a slight overhang for easy removal.

Step 2: To a large mixing bowl, add 150g softened salted butter, 130g caster sugar, and 100g soft brown sugar. Cream them together until smooth and fluffy.

Step 3: Next, add one medium egg and a teaspoon of vanilla extract to the bowl. Mix well until smooth.

Step 4: Now add 250g of self-raising flour to the wet mixture. Mix it in and once it begins to stick, put your hands in and press it all together into a ball of dough. If the dough feels a bit sticky, add more flour and if it's too dry or crumbly, add a small splash of milk to help it come together.

Step 5: Add 100g of red and green mini M&Ms along with 25g of milk chocolate chips and 25g of white chocolate chips. You can set a few aside for the topping if you like. Use your hands to gently knead them into the dough until evenly distributed.

Step 6: Transfer the dough to your lined tin and press it down evenly. You can use a piece of baking paper in between your hands and the dough, to prevent getting fingerprints in it.

Step 7: Sprinkle the leftover M&Ms and chocolate chips on top, pressing them gently into the surface so they stick.

Step 8: Bake for 22-25 minutes, until golden brown on top.

Step 9: Let the cookie cool in the tin then cut it into slices. For an extra sturdy, chewy texture, place it in the fridge for 1-2 hours until solid before cutting it.

Tips for the perfect cookie bars

Use a mix of caster sugar and soft light brown sugar for the best flavour and texture.
Let the cookie slab firm up in the fridge for 1-2 hours before you cut it. This is not essential but will give a cleaner cut and a chewier texture.
If you want to use a different size of tin than the ones I recommend, use my cake pan converter tool to get the correct ingredient quantities. This will prevent thin, underbaked or burnt Christmas cookie bars.

FAQ

How should I store Christmas M&M cookie bars?

Keep them in an airtight container. You can store them at room temperature if you like but I recommend storing them in the fridge to keep them nice and chewy. They'll keep well for about 5 days.

Can I freeze them?

Yes, M&M Christmas cookie bars are perfect for freezing. Just pop them into an airtight container and freeze for up to 3 months. Alternatively, you can freeze them on a baking tray then once they're solid, transfer them to a freezer bag. To defrost, just let them sit out at room temperature for an hour or two.

Can I make this recipe gluten-free?

Yes! Just use an equal amount of gluten-free self-raising flour. I'd recommend using a flour blend with xanthan gum in it for best results.

More Christmas cookies

I hope you like these Christmas M&M cookie bars! If you make them at home, please leave a comment or rating to let me know what you think. Enjoy!