Christmas M&M Cookie Bars

It’s that time of year again, when the scent of baking fills our little house, and the sound of Mariah Carey (much to my husband’s chagrin!) blasts from the kitchen. This year, we’ve been busy perfecting our Christmas M&M Cookie Bars. After a few batches (and a lot of M&M “quality control” by the kids), we’ve landed on a recipe that’s not only ridiculously easy but also creates the most festive, chewy, and utterly irresistible treat. I promise, these bars will be the star of your Christmas baking – and the kids will love helping!

Why This Recipe Works

As a busy mum to two very active children, I know how precious time is, especially during the festive season. These Christmas M&M Cookie Bars are designed to be simple, stress-free, and, most importantly, delicious! After eight years of tweaking recipes for FamiliesRecipes.com, I’ve learned a thing or two about what works for real families.

• Straightforward Method: No complicated techniques or fancy equipment needed. Just basic ingredients and a simple mixing method.
• Child-Approved: My little ones are brutally honest critics, and they absolutely adore these bars. They love helping to decorate them with the M&Ms, too!
• Budget-Friendly: Using readily available ingredients from your local supermarket means you won’t have to break the bank to create a stunning and tasty treat.

Ingredients

• 115g (1/2 cup) unsalted butter, softened
• 150g (3/4 cup) granulated sugar
• 50g (1/4 cup) light brown sugar, packed
• 1 large egg
• 1 teaspoon vanilla extract
• 200g (1 1/2 cups) plain flour
• 1/2 teaspoon baking powder
• 1/4 teaspoon salt
• 200g (1 1/4 cups) Christmas M&Ms, divided

Ingredient Notes

Unsalted Butter: I always use unsalted butter in baking to control the amount of salt in the final product. If you only have salted butter, simply omit the added salt in the recipe.

Light Brown Sugar: The brown sugar adds moisture and a lovely chewy texture to the bars. Dark brown sugar will also work, but the flavour will be a bit more intense.

Vanilla Extract: A good quality vanilla extract makes a real difference. If you’re feeling fancy, try using vanilla bean paste for an even richer flavour.

Christmas M&Ms: Of course, these are essential for the festive touch! You can find them in most UK supermarkets in the run-up to Christmas. Feel free to substitute with regular M&Ms or other festive sprinkles if you prefer.

Step-by-Step Instructions

Step 1: Preheat and Prep. Preheat your oven to 180°C (160°C fan/Gas Mark 4). Grease and line an 8×8 inch (20×20 cm) square baking tin with baking parchment, leaving an overhang for easy removal. This is crucial for getting clean, even bars.

Step 2: Cream the Butter and Sugars. In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy. I use an electric mixer for this, but you can definitely do it by hand – just make sure the butter is really soft.

Step 3: Add Egg and Vanilla. Beat in the egg and vanilla extract until well combined. Don’t worry if the mixture looks a little curdled at this point, it will come together when you add the dry ingredients.

Step 4: Combine Dry Ingredients. In a separate bowl, whisk together the flour, baking powder, and salt. This ensures the baking powder is evenly distributed, leading to a better rise.

Step 5: Gradually Add Dry Ingredients to Wet Ingredients. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix, as this can result in tough bars.

Step 6: Fold in M&Ms. Fold in 150g of the Christmas M&Ms, reserving the remaining 50g for topping. The kids love helping with this part – although a fair few M&Ms usually disappear in the process!

Step 7: Press into Tin and Top. Press the cookie dough evenly into the prepared baking tin. Sprinkle the remaining 50g of M&Ms over the top, pressing them gently into the dough.

Step 8: Bake. Bake for 20-25 minutes, or until the edges are golden brown and the centre is just set. A toothpick inserted into the centre should come out with a few moist crumbs attached.

Step 9: Cool and Cut. Let the bars cool completely in the tin before lifting them out using the parchment paper overhang. Cut into squares and serve. Patience is key here – if you try to cut them while they’re still warm, they’ll be too crumbly.

My Kitchen Tips & Tricks

• Don’t Overmix: Overmixing the dough develops the gluten in the flour, resulting in tough cookie bars. Mix until just combined for a tender, chewy texture.
• Soften the Butter Properly: Make sure your butter is softened but not melted. If it’s too soft, the bars will spread too much during baking.
• Line the Tin: Lining the baking tin with parchment paper makes it much easier to lift the bars out cleanly. Leave an overhang for even easier removal.
• Press M&Ms into the Dough: Pressing the M&Ms into the dough before baking helps them to adhere better and prevents them from falling off when you cut the bars.
• Cool Completely: As mentioned before, letting the bars cool completely before cutting is essential for clean, even slices. I often pop them in the fridge for a quicker cool down.
• Child-Friendly Tip: Let the little ones help with decorating! It’s a great way to get them involved in the baking process (and keep them entertained for a few minutes). Just be prepared for a bit of mess!
• Flavour Boost: Add a pinch of cinnamon or nutmeg to the dry ingredients for an extra touch of festive warmth.

Storage & Meal Prep

These Christmas M&M Cookie Bars are perfect for making ahead and storing for festive gatherings. Here’s how I manage them in my busy household:

Storage: Store the cooled bars in an airtight container at room temperature for up to 3 days, or in the fridge for up to 5 days. They’re also freezer-friendly – wrap them tightly in cling film and store in a freezer bag for up to 2 months. Thaw at room temperature before serving.

Make-Ahead: You can prepare the dough ahead of time and store it in the fridge for up to 2 days. Just bring it to room temperature for about 30 minutes before pressing it into the tin and baking.

Batch Cooking: This recipe doubles easily, so feel free to make a larger batch if you’re catering for a crowd. Simply double all the ingredients and use a larger baking tin.

Substitutions & Variations

I’m all about making recipes work for everyone, so here are a few substitutions and variations I’ve tried:

Gluten-Free: I’ve successfully made these bars gluten-free by using a gluten-free all-purpose flour blend. Just be sure to add a teaspoon of xanthan gum for binding.

Dairy-Free: You can substitute the butter with a dairy-free butter alternative. Just make sure it’s one that’s suitable for baking.

Different M&Ms: Whilst Christmas M&Ms are my favourite, feel free to use any variety you like! I’ve used peanut M&Ms, pretzel M&Ms, and even mini M&Ms with great results.

Other Mix-Ins: Get creative with other mix-ins! Try adding chopped nuts, chocolate chips, dried cranberries, or even mini marshmallows.

Frequently Asked Questions

Can I prepare this the night before?

Absolutely. In fact, I often do this on Sunday evenings before the busy school week. Simply prepare everything up to the baking stage, cover tightly, and refrigerate. Bring it to room temperature for 15 minutes before cooking, and you’ll save yourself precious morning time.

How do I know when the bars are done?

The bars are done when the edges are golden brown and the centre is just set. A toothpick inserted into the centre should come out with a few moist crumbs attached. Be careful not to overbake them, as this will result in dry, crumbly bars.

Can I use a different type of sugar?

While I recommend using a combination of granulated and light brown sugar for the best texture and flavour, you can experiment with other types of sugar. Dark brown sugar will work, but it will give the bars a more intense flavour. You can also use caster sugar instead of granulated sugar.

How should I store the leftovers?

Store the cooled bars in an airtight container at room temperature for up to 3 days, or in the fridge for up to 5 days. They can also be frozen for longer storage.

Will my children like these?

In my experience, children absolutely adore these Christmas M&M Cookie Bars! The colourful M&Ms and sweet, chewy texture are always a hit. Plus, they love helping to decorate them!

Can I make these in a larger baking tin?

Yes, you can easily double this recipe and bake it in a 9×13 inch baking tin. Just be sure to increase the baking time by a few minutes.

Can I add nuts to these cookie bars?

Absolutely! Chopped walnuts, pecans, or almonds would be a delicious addition to these bars. Simply fold them into the dough along with the M&Ms.

Serving Suggestions (Optional)

These Christmas M&M Cookie Bars are delicious on their own, but here are a few serving suggestions to elevate them even further:

• Serve with a glass of cold milk or a cup of hot cocoa.
• Drizzle with melted chocolate or a simple icing.
• Break them into smaller pieces and use them as a topping for ice cream.
• Pack them in festive gift boxes as a homemade Christmas gift.

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