Gooey, chewy brown-butter M&M cookie bars—packed with melty chocolate and colorful M&Ms—are baked in a square pan until the edges turn golden brown. The nutty, caramel-like flavor from the brown butter elevates these bars into something truly special.
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This is my first Christmas recipe on the blog — I’m so excited to share it. If you’re coming from my YouTube channel SweetTreats, thank you for following along. I introduced myself recently, and if you want to learn more about me, check the About Me section on the blog. I can’t wait to grow this baking community with you.
Let’s Talk Brown Butter
Brown butter adds a deep, nutty, caramel-like note that transforms ordinary baked goods into something extraordinary. To make brown butter, melt butter over medium heat and let it cook a few minutes past the melting point. As the water evaporates, the milk solids will foam and then begin to brown on the bottom of the pan. When the butter turns a golden-brown color and gives off a toasty, nutty aroma, remove it from the heat and transfer it to a heatproof bowl to stop the cooking. It’s easier than it sounds and worth mastering for everything from cookies to cakes.
Steps to Creating Brown Butter
- Place butter in a light-colored saucepan over medium heat and stir as it melts.
- When it starts to foam and sizzle, continue whisking occasionally while it cooks down.
- Watch carefully; after several minutes the milk solids will turn light brown. Depending on the amount of butter, this can take 3–6 minutes or a bit longer.
- When the foam subsides and the butter is golden with a nutty aroma, remove it from heat and pour it into a heatproof bowl to stop the cooking.
- Tip: Don’t leave the butter in the hot pan while you prep other ingredients — it can burn quickly.
Video Recipe for Brown Butter Holiday M&M Cookie Bars
I’ve made these bars many times, with and without seasonal M&Ms. They’re a true crowd-pleaser: soft and golden on the outside, gooey and chocolatey inside. The brown butter brings a rich depth, and flaky sea salt on top balances the sweet and salty perfectly.
After browning the butter, everything comes together in one bowl—minimal fuss and easy cleanup. Stir in the mix-ins, press the dough into a lined 9×9 pan, and bake until the edges are golden. Simple steps, spectacular results.
Brown Butter Holiday M&M Cookie Bars
Pin Recipe
Ingredients
- 1/2 cup brown butter see directions above for browning butter
- 1/4 cup brown sugar
- 1/4 cup white sugar
- 2 tsps vanilla
- 1 egg
- 1 cup flour
- 1/2 tsp baking soda
- 1/3 cup chocolate chips
- 1/3 cup M&Ms
Instructions
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Brown the butter following the directions above.
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Preheat the oven to 350°F (175°C).
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In a bowl, whisk together the brown butter and both sugars until combined.
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Add the egg and vanilla and whisk until smooth.
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Fold in the flour and baking soda with a spatula until just combined.
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Stir in the chocolate chips and M&Ms.
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Press the dough into a lined and lightly greased 9×9-inch square pan.
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Bake 18–20 minutes, until the edges are golden brown.
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Cool in the pan, then slice and enjoy.
