These Christmas M&M cookie bars are soft and chewy with a buttery vanilla flavor. They’re quick and easy to make and look festive with red and green M&Ms. If you prefer extra-thick bars loaded with chocolate, these are for you. 
Why You’re Going to Love these Christmas M&M Cookie Bars
Cookie bars are faster and simpler than drop cookies: no chilling, no rolling dough into balls, and no sticky hands. These M&M cookie bars are thick, chewy and tender with plenty of holiday M&Ms and chocolate chips. Bake them a little less for a gooey, blondie-like texture, or bake a touch longer for a softer, chewier bar that still stays tender.
Making Cookie Bars
Here’s a straightforward method to make these cookie bars.
- Preheat the oven to 350°F (180°C). Line a 9×13-inch (23 x 33 cm) pan with parchment paper leaving an overhang, or lightly grease the pan.
- In a large bowl whisk together melted butter, brown sugar and granulated sugar until no pools of butter or lumps of sugar remain. Using melted butter gives the bars a chewier texture.
- Whisk in the eggs and vanilla extract until incorporated and no egg pieces remain.
- In a separate bowl whisk together the dry ingredients: all-purpose flour, cornstarch, baking soda and salt. Cornstarch helps give the bars extra chew.
- Fold the dry ingredients into the butter mixture until just combined. Stir by hand with a spatula or whisk; an electric mixer can be used but stop once there are no streaks of flour.
- Fold in the red and green M&Ms and chocolate chips. Cookie bars are great for packing in extra mix-ins compared with rolled cookies.
- Spoon the batter into the prepared pan and smooth the top. If you like, press a few extra M&Ms and chocolate chips onto the surface.
- Bake for 25–30 minutes or until the top is golden. Bake 25–27 minutes for slightly gooey, blondie-like bars; bake closer to 30 minutes for a firmer, chewy bar. Allow to cool in the pan before slicing.
Note: This formula is designed for cookie bars. If you attempt to bake drop cookies with this batter, they may spread too thin. For a cookie version, use a recipe specifically developed for Christmas M&M cookies.
Freezing Cookie Bars
These bars freeze very well. Make sure they are completely cooled before freezing. If baked in a disposable pan, wrap the whole pan tightly and freeze. Otherwise slice the cooled bars, wrap pieces individually or place slices in a freezer-safe bag.
Thaw frozen bars in the refrigerator, then bring to room temperature on the counter before serving to avoid a gummy texture.
Thick, chewy and tender, these Christmas M&M cookie bars are loaded with M&Ms and chocolate chips and make an easy festive treat. They’re simple to prepare, freeze well, and are perfect for holiday gatherings or gifting.
Equipment
- 9×13 inch (23 x 33 cm) baking pan
Ingredients
- 1 cup (226 g) unsalted butter, melted and slightly cooled
- 1 cup (210 g) brown sugar, light or dark
- 1/2 cup (100 g) granulated sugar
- 2 large eggs
- 2 teaspoons vanilla extract
- 2 1/2 cups (313 g) all-purpose flour
- 2 teaspoons cornstarch
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 3/4 cup (about 150 g) red and green M&Ms
- 3/4 cup (135 g) chocolate chips
Instructions
- Preheat oven to 350°F (180°C). Line a 9×13-inch pan with parchment paper leaving an overhang, or lightly grease the pan.
- Whisk melted butter with brown and granulated sugars until fully combined and no butter pools remain.
- Whisk in the eggs and vanilla until blended.
- In a separate bowl, whisk flour, cornstarch, baking soda and salt.
- Fold the dry ingredients into the wet until smooth and no flour streaks remain.
- Stir in the M&Ms and chocolate chips.
- Spread batter evenly in the prepared pan. Optionally press extra M&Ms on top.
- Bake 25–30 minutes until the top is golden; shorter for gooey bars, longer for firmer bars. Cool completely in the pan.
- If you used parchment, lift bars out with the overhang and slice on a cutting board. If greased, slice in the pan.
Notes
- Pan sizes: This recipe can be halved for an 8×8-inch (20 x 20 cm) pan; bake about 20–25 minutes.
- M&Ms: A standard 10-ounce bag may leave extra M&Ms.
- Storage: Store cooled bars in an airtight container at room temperature up to 4 days. Freeze wrapped bars up to 2 months; thaw in the fridge before bringing to room temperature.
- Nutrition: Values are estimates per bar when the pan is cut into 15 pieces.
Nutrition (per large bar, estimate)
Calories: 375 kcal, Carbohydrates: 51 g, Protein: 4 g, Fat: 18 g, Saturated Fat: 11 g, Sugar: 33 g.