These M&M cookie bars combine nutty browned butter, gooey semi-sweet chocolate chips, and crunchy candies for a treat that’s as colorful as it is delicious.
Recipe Science
- Melting the butter helps create a soft and chewy cookie bar by dissolving the sugar more effectively, resulting in a denser dough.
- Cooking butter until the milk solids toast creates brown butter, adding a nutty aroma and rich caramelized flavor.
- Semi-sweet chocolate chips balance the sweet and crunchy texture of the candy-coated M&M’s.
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Why It Works
If you love M&M cookies but want a faster option, these cookie bars are the perfect solution. Skip the rolling and shaping—just make the dough, spread it into a pan, and bake! They’re ideal for sharing and can be sliced into large bars or bite-sized pieces, perfect for cookie trays.
For extra flavor, take a few minutes to brown the butter—it adds a rich butterscotch taste and a beautiful golden hue. When served warm, semi-sweet chocolate chips provide a touch of bittersweet cocoa and a wonderfully melty texture. These bars also make fantastic festive gifts, ready to package and share! Give my blondie recipe a try if you enjoy a nutty cookie bar.
Ingredients You’ll Need
- Flour: For a soft and chewy texture, use all-purpose flour for a moderate protein level between 10 to 13%.
- Butter: Use unsalted butter to add richness to the cookie dough.
- Sugar: Light brown sugar adds a hint of molasses flavor. This type of sugar is a humectant, which keeps the bars soft.
- Leavening Agents: Baking powder and eggs provide lift so that the bars aren’t too dense.
- Flavoring: Vanilla extract adds a strong, sweet baked aroma. Salt enhances the butterscotch flavor of the browned butter.
- Chocolate: I use candy-coated M&M’s and semi-sweet chocolate chips. The bittersweet cocoa balances the sweet candy.
See the recipe card below for all ingredients and measurements (US and metric).
Ingredient Substitutions
This M&M cookie bars recipe is easy to customize! Try these tasty options:
- M&M’s: Try the mini variety for more distribution throughout the dough. Go classic with a rainbow of colors, or during the holidays, make them festive for Halloween, Christmas, and Easter. For extra flavor, try candies filled with nuts, peanut butter, or caramel.
- Chocolate: Add white, dark, or other types of chocolate. Add chopped chocolate or disc for a more gourmet appearance.
- Flavor: Make the cookie base exciting with almond extract, coconut, peppermint, or anise.
- Nuts: Instead of walnuts, try roasted peanuts, almonds, or pecans. Toasted coconut would be yummy, too!
- Toppings: Add colorful sprinkles and whipped cream for a birthday or holiday celebration. Drizzle on caramel sauce for decadence.
How to Make M&M Cookie Bars
Step 1: Heat the Oven
Position the oven rack in the center to ensure even baking. Preheat the oven to 350ºF (177ºC), as this temperature optimizes the Maillard reaction for golden-brown edges.
Tips for Perfect Execution: Line a 13×9-inch metal cake pan with foil or parchment paper, allowing for an overhang on the sides. This overhang acts as a sling, making lifting the cookie bars easier without breaking.
Step 2: Brown the Butter
Melting the butter and cooking until the milk solids are toasted transforms the taste and aroma. The brown butter releases a nutty aroma, a sign of milk solids caramelizing, which typically takes 2 to 3 minutes. Immediately transfer to a large bowl to prevent overcooking.
Pro Tip: Allow the butter to cool to below 144ºF (62ºC) to avoid prematurely cooking the eggs in the recipe when combined.
Step 3: Mix the Dry Ingredients
Whisk together the flour, baking powder, and salt. This step evenly distributes the leavening agent and salt throughout the flour, ensuring consistent rise and balanced flavor in the cookie bars.
Step 4: Mix the Sugar and Eggs
Add the brown sugar to the cooled browned butter and whisk until fully combined. The sugar dissolves slightly, creating a smoother mixture and enhancing the caramelized flavor.
Incorporate the eggs and vanilla extract, whisking until the mixture becomes smooth and shiny. This process aerates the mixture slightly, helping to create a tender and chewy texture in the cookie bars.
Step 5: Make the Dough
Gently fold the flour mixture into the browned butter mixture. Be careful not to overmix, as this can overdevelop the gluten in the flour, resulting in denser cookie bars.
Step 6: Add the Mix-Ins’
Incorporate the chocolate chips and M&M candies into the dough until evenly distributed. This ensures that every bite of the cookie bars with M&M’s has a balanced mix of chocolate and candy while avoiding overworking the dough.
Step 7: Bake
Spread the mixture into the pan, targeting an even thickness for consistent baking. Bake until the surface is lightly golden brown and the edges are set, about 20 minutes. This timing allows the center to remain slightly chewy while the edges achieve a crisp texture.
Expert Tip: Press additional chocolate chips and M&M candies onto the surface for a visually appealing finish and extra bursts of chocolate flavor.
Step 8: Cool
Place the baking pan on a wire rack and allow the chocolate chip cookie bars to cool to room temperature, which takes about one hour. Cooling in the pan ensures the structure sets, preventing the center from breaking if removed while too hot and delicate. Want to enjoy the bars warm? Slice it directly in the pan and carefully lift the pieces with a spatula.
Step 9: Slice
Once cooled completely, use the foil or parchment paper overhang to gently lift the cookie out of the pan and transfer it to a cutting board. Slice the cookie into 2-inch pieces or to the desired size.
This chewy M&M cookie bars recipe is perfect to dip in a glass of milk! I made these festive for Christmas so that the kids can leave a few pieces for Santa.
Frequently Asked Questions
Mini M&M’s work great, adding smaller bursts of chocolate flavor through the candy. There are so many varieties of candy now! Try M&M’s filled with caramels, peanuts, almonds, or peanut butter.
No, you don’t have to brown the butter for these cookie bars. The butter can be melted instead, resulting in a lighter-colored bar with a stronger vanilla flavor than the nutty, caramel-like notes of browned butter. This is an excellent option if you prefer a more subtle, traditional cookie flavor or want to save a few minutes during preparation.
These cookies keep very well, making them convenient for gifts or holiday cookie swaps. Store them in an airtight container at room temperature for up to 7 days to maintain their freshness. For extended storage, wrap the cookie bars tightly in plastic wrap, place them in a freezer bag, and freeze them for up to 3 months.
More Cookie Recipes
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M&M Cookie Bars
Ingredients
- 1 ½ cups all-purpose flour
- 1 teaspoon baking powder
- ½ teaspoon table salt
- 12 tablespoons unsalted butter, cut into slices
- 1 ½ cups light brown sugar, packed
- 2 large eggs
- 1 tablespoon vanilla extract
- ½ cup semi-sweet chocolate chips, more for topping
- ½ cup M&M candies, more for topping
Instructions
- Heat the Oven – Set the oven rack to the middle position. Heat the oven to 350ºF (177ºC). Line a 13×9 metal cake pan with foil or parchment paper. Leave some overhang on the sides to make the cookie easy to lift out. Lightly grease the pan with nonstick cooking spray.
- Brown the butter – Heat the butter slices in a 10-inch skillet over medium heat, swirling to melt evenly. Stir and cook, scraping the bottom of the pan with a spatula, until butter is golden brown and nutty in aroma, 2 to 3 minutes. Immediately transfer to a large bowl, scraping all of the bits from the pan. Cool to below 144ºF (62ºC).
- Mix the Dry Ingredients – In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
- Mix the Sugar and Eggs – To the cooled browned butter, add the brown sugar. Whisk until combined. Add the eggs and vanilla. Whisk until smooth and shiny.
- Make the Dough – Add the flour mixture to the butter mixture. Fold together until no flour streaks remain. Do not over mix!
- Add the Mix-Ins' – Add the chocolate chips and M&M candies. Stir until combined in the dough.
- Bake – Evenly spread the dough in the prepared baking pan. Press some chocolate chips and M&M candies into the surface. Bake in the center of the oven until the surface is lightly golden brown and the edges are set, 20 to 22 minutes.
- Cool – Transfer the cookie bars to a wire rack to cool in the pan until it's room temperature. This can take about 1 hour. If removed when hot, it will break in the middle. To serve warm, slice in the pan and remove the pieces with a spatula.
- Slice – Carefully use the foil or paper overhang to lift the cookie out of the pan. Place on a cutting board, remove lining, and slice into 2-inch-sized pieces.
Recipe Video
Notes
- Using Melted Butter: The butter can be melted and not browned. It will yield a lighter color and a stronger vanilla flavor instead of butterscotch.
- Storing: Store in an airtight container for up to 7 days. Wrap the blondies, place them in a freezer bag, and freeze them for up to 3 months.
Nutrition Facts
Percent Daily Values are based on a 2000-calorie diet. All nutritional information is based on estimated third-party calculations. Each recipe and nutritional value will vary depending on the brands you use, measuring methods, and portion sizes per household.
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