Christmas M&M Cookie Bars take everything you love about a classic cookie and turn it into an easy, sliceable bar loaded with red and green candy. One bowl and one pan get you a thick, chewy base packed with M&M’s from edge to edge, with no scooping or batch baking required. They come together faster than a full batch of individual cookies and slice into neat squares perfect for a holiday dessert tray. Once they’re out of the oven and cooled, they’re ready to stack, gift, or serve alongside the rest of your Christmas cookie lineup.

Why These Christmas M&M Cookie Bars Belong on Your Christmas Dessert Table

Cookie bars solve the biggest headache of holiday baking, which is standing at the oven scooping and rotating tray after tray of individual cookies. This recipe uses one pan and one bake time, so a big batch is done in a single trip to the oven.

The red and green M&M’s do all the decorating work, so there’s no piping, no icing, and no fussy finishing touches needed to make these look festive. They’re an easy win for anyone short on time during the busiest baking week of the year.

And because they slice into neat, even squares, they’re simple to portion out for a cookie tray, a lunchbox, or a gift box without any extra effort.

Everything You’ll Need

The ingredient list is refreshingly short, and there’s plenty of room to customize it with what you already have on hand.

2 1/4 cups all-purpose flour
1 teaspoon baking soda
1/2 teaspoon salt
1 cup unsalted butter, softened
3/4 cup granulated sugar
3/4 cup brown sugar, packed
2 large eggs
2 teaspoons vanilla extract
1 1/2 cups red and green M&M’s, divided

Ingredient Swaps & Easy Substitutions

Holiday-colored M&M’s give the most festive look, but regular M&M’s or another holiday candy-coated chocolate work just as well if that’s what’s in the pantry. Salted butter can stand in for unsalted if that’s all you have; just leave out the added salt from the recipe. A mix of brown and white sugar keeps the bars chewy, but you can use all brown sugar for a slightly deeper, more caramel-like flavor.

Kitchen Tools You’ll Want

9×13-inch baking pan
Parchment paper
Stand mixer or hand mixer
Mixing bowls
Offset spatula, for spreading the batter

Let’s Make Them

Once everything is prepped, these bars come together in just a few easy stages.

Mix the dry ingredients: Whisk together the flour, baking soda, and salt in a bowl and set aside.
Cream the butter and sugars: Beat the butter, granulated sugar, and brown sugar together until light and fluffy.
Add the eggs and vanilla: Beat in the eggs one at a time, then mix in the vanilla extract.
Combine: Gradually mix in the dry ingredients until just combined into a thick dough.
Fold in the M&M’s: Stir in most of the M&M’s, saving a handful to press on top.
Spread into the pan: Press the dough into a parchment-lined 9×13-inch pan in an even layer, then press the reserved M&M’s on top.
Bake: Bake at 350°F for 25 to 30 minutes, until the edges are golden and the center is just set.
Cool and slice: Let the bars cool completely in the pan before lifting out and slicing into squares.

Host’s Tips for the Best Christmas M&M Cookie Bars

Press the dough evenly into the corners of the pan so the bars bake at a consistent thickness and don’t end up with thin, overbaked edges. Save some M&M’s to press on top after spreading the dough, since this keeps the candy from sinking and gives the bars that classic bakery-case look. Let the bars cool fully in the pan before slicing, since cutting them warm can leave the centers gummy instead of set. A sharp knife wiped clean between cuts gives the neatest squares.

Easy Ways to Make Them Your Own

Add a half cup of white chocolate chips along with the M&M’s for extra sweetness and a slightly different texture. Swap the vanilla for almond extract for a subtle flavor twist, or add a quarter teaspoon of peppermint extract for a minty holiday version. For a thicker, more indulgent bar, press half the dough into the pan, add a layer of crushed candy canes or extra M&M’s, then top with the remaining dough before baking.

Perfect Occasions & What to Serve Alongside

These bars are perfect for cookie exchanges, office parties, and holiday potlucks where you need something that feeds a crowd without much fuss. They also pack well into lunchboxes or gift tins for teachers and neighbors. Serve them alongside hot cocoa or a cold glass of milk, or add them to a dessert board next to truffles and reindeer cookies.

Make-Ahead & Serving Notes

These bars can be baked up to 3 days ahead and stored in an airtight container at room temperature. They also freeze well for up to 2 months; wrap individual bars tightly and thaw at room temperature for about an hour before serving. The dough can also be pressed into the pan and refrigerated for up to a day before baking if you’d rather split up the prep.

Still have a question? Here are a few of the most common ones readers ask before making these Christmas M&M Cookie Bars.

Why are my cookie bars too doughy in the middle?

This usually means they need a few more minutes in the oven, or the pan wasn’t fully preheated before baking. Bake until the center looks just set and the edges are lightly golden, then let the bars finish setting as they cool in the pan.

Can I use a different size pan?

Yes, though bake time will need to change. A smaller pan will give thicker bars that need a few extra minutes, while a larger pan will give thinner bars that bake faster.

Why did my M&M’s melt into the dough?

This can happen if the oven runs hot or the bars are left in too long. Pressing extra M&M’s on top just before baking, rather than only folding them into the dough, helps keep some intact and visible on the surface.

Can I make these ahead for a party?

Yes, they keep well for a few days stored in an airtight container at room temperature. You can also freeze baked, sliced bars and thaw them the morning of your event.

Do I need to chill the dough before baking?

No, this dough goes straight into the pan without any chilling required, which is part of what makes these bars faster than a full batch of individual cookies.

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