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Nothing fills my kitchen with more warmth and cheer than a batch of Christmas cookie bars. These beauties come together fast with cake mix and festive candy so they are perfect when holiday chaos makes you crave a homemade treat in a hurry. Every bite bursts with soft cookie texture and M and Ms that melt in your mouth making them a yearly favorite for my family and neighbors.
I first tried these bars when scrambling to bring something special to my daughter’s school party. Now we bake them every December and leave them for Santa too.
Ingredients
- White cake mix: From a 15 ounce box gives you fudgy cookie texture without fuss. Choose a reputable brand for the best flavor
- Salted butter, melted: For rich taste and extra tenderness. Try to use real dairy butter for softness
- Eggs: Help bind the dough and add structure. Look for fresh large eggs with no cracks
- Holiday M and Ms: Provide crunch color and chocolate in every bite. The red and green candies add Christmas spirit
- White chocolate chips: For creamy pockets of sweetness. Select chips that are shiny with no white streaks
Instructions
- Prep the Oven and Pan:
- Set your oven to 350 degrees and allow it to preheat. Coat a 9 by 13 inch baking dish with nonstick spray so the bars lift out neatly
- Mix Wet Ingredients:
- Crack eggs into a large mixing bowl. Beat well by hand or with a mixer until blended
- Add Cake Mix and Butter:
- Pour the white cake mix over the beaten eggs. Add the melted butter and mix until a slightly thick dough forms. Take care to scrape all the dry mix from the bowl’s edges
- Fold In Mix Ins:
- Stir in one cup of holiday M and Ms and all of the white chocolate chips just until everything looks evenly distributed
- Spread Into Pan:
- Use a rubber spatula or lightly oiled hands to press and spread the dough in the pan making sure it reaches the corners and forms an even layer
- Decorate the Top:
- Sprinkle the remaining half cup of M and Ms across the surface. Press them down gently so they stick but stay visible
- Bake:
- Place the pan in the oven. Bake for twenty to twenty five minutes. Watch closely at the end and test with a toothpick inserted in the center. If it comes out clean with a few crumbs the bars are ready. They should look golden but still feel a bit soft in the center
- Cool and Slice:
- Let the pan cool completely on a rack so the bars set up and are easier to cut neatly into squares
The crunchy M and Ms on top are always my favorite part. I remember the year my son tried to sneak a few extra candies after decorating the bars and ended up laughing with powdered sugar on his nose. Baking these bars truly brings our family together.
Storage Tips
Keep leftovers in a tightly sealed food container at room temperature and they will stay fresh for about two to three days. For longer storage wrap bars in plastic wrap and freeze in a freezer bag. Let them thaw before you enjoy.
Ingredient Substitutions
You can use any color or holiday mix of M and Ms for birthdays or other celebrations. If you run out of white chocolate chips try semisweet mini chips or chopped nuts for a little crunch.
Serving Suggestions
Serve these cookie bars straight up or with a glass of cold milk. I like to cut them into small squares for a holiday platter or even crumble them over vanilla ice cream for a show stopping dessert.
Cultural and Holiday Traditions
Baking cookies and bars is a classic American holiday tradition. These cookie bars are inspired by the joy of Christmas cookie swaps when families trade sweet treats and stories. The red and green candies make every bite a celebration.
Seasonal Adaptations
Try pastel M and Ms and lemon zest for spring — Swap for Halloween candies in October — Decorate with edible gold or silver sprinkles for a special occasion
Success Stories
Friends have told me these bars are the first to vanish from any dessert table. One reader shared she made them for a cookie walk at her church and every square was gone in minutes
Freezer Meal Conversion
You can bake ahead and freeze the sliced bars in layers with parchment paper between each stack. They thaw quickly and taste just as soft and sweet which makes them perfect for busy holiday weeks.
Baking these Christmas cookie bars is our family’s favorite December tradition. They disappear quickly—so don’t forget to save a piece for Santa.
Common Recipe Questions
- → Can I use regular M&M'S instead of holiday colors?
Yes, any M&M’S variety will work, but holiday colors add a festive touch for winter gatherings.
- → How do I know when the bars are done baking?
Insert a toothpick into the center. If it comes out clean with a few moist crumbs, they’re ready. Don't overbake.
- → Can I substitute the white cake mix?
Yellow cake mix or vanilla cake mix can be used as an alternative to white cake mix.
- → How should I store leftovers?
Keep bars in an airtight container at room temperature for up to 3 days for best freshness and texture.
- → What is the best way to cut the bars cleanly?
Allow the bars to cool completely, then use a sharp knife lightly coated with nonstick spray for clean edges.