M&M Cookie Bar Recipe

If you’re craving a dessert that’s easy to make, full of color, and perfectly sweet, I’ve got the perfect treat for you. This M&M Cookie Bar Recipe combines the best of classic cookies and chewy bars in one sliceable pan, and trust me—you’re going to want to keep these bars handy for every occasion. Whether it’s a last-minute party or that afternoon sweet tooth calling, this recipe is fan-freaking-tastic and super forgiving for even beginner bakers.

this Recipe

Ingredients You’ll Need

To get that perfect M&M cookie bar, it’s all about simple, reliable ingredients coming together. I always recommend using room temperature butter—it makes a huge difference for creamy, well-mixed dough.

• Unsalted Butter: Using unsalted lets you control the saltiness perfectly—plus, room temp helps with easy creaming.
• Light Brown Sugar: Gives the bars a lovely caramel undertone and keeps them moist.
• Granulated Sugar: Adds sweetness and helps build the right texture.
• Eggs: Helps bind everything together and adds moisture.
• Vanilla Extract: Always enhances the flavor and gives that classic cookie aroma.
• All-Purpose Flour: The base for structure—don’t swap this for self-rising unless you adjust the baking soda.
• Baking Soda: Gives a gentle lift so the bars aren’t too dense.
• Salt: I use kosher salt for better flavor, but regular salt works fine.
• Chocolate Chips: Melts into pockets of chocolaty goodness throughout the bars.
• M&M’s: These colorful candies make every bar joyful and a little extra fun.

Variations

One of the best parts about this M&M Cookie Bar Recipe is how easy it is to make it your own. I’ve experimented with a bunch of variations to give you ideas—because baking should be fun and flexible, not rigid.

• Holiday M&Ms: I swap in red and green M&M’s during Christmas, and pastel ones at Easter—it makes the bars festive without extra effort.
• Nutty Addition: Adding chopped walnuts or pecans adds a lovely crunch, especially if you like that texture contrast.
• Peanut Butter Swirl: One time, I swirled peanut butter into half the batter before baking—it was a delicious twist that my husband never forgets.
• Gluten-Free: Use a 1:1 gluten-free flour blend and watch for slightly different baking times, but it works well!

How to Make M&M Cookie Bar Recipe

Step 1: Cream the Butter and Sugars

Start by preheating your oven to 325°F and lining your baking pan with parchment or foil for easy removal later—I love using a 9×13-inch pan for thick bars, but a bigger pan works if you want thinner ones. Then beat together the room temperature butter with both the light brown sugar and granulated sugar. Use either a stand mixer or handheld electric mixer and cream them for about one minute until the mixture is fluffy and smooth. I’ve found that not rushing this part really helps with a tender final texture.

Step 2: Add Eggs and Vanilla

Once your butter and sugars are creamed, add in the eggs one at a time, mixing after each addition. Don’t forget the vanilla extract here—that little splash amps up the flavor more than you’d expect. Mix everything until it’s just combined; overmixing at this stage can make your bars too dense.

Step 3: Stir in Dry Ingredients

In a separate bowl, whisk together the all-purpose flour, baking soda, and salt. Gradually add this dry mix to the wet ingredients and fold gently just until there are no streaks of flour left. The key is to stir enough to combine but avoid overworking the dough.

Step 4: Mix in the Chocolate and M&M’s

Fold in one cup of chocolate chips and an equal amount of M&M’s, saving about a quarter cup of each to scatter on top before baking. This trick gives the surface a gorgeous look that’s as inviting as the inside.

Step 5: Bake to Perfection

Press your dough evenly into the prepared pan, then sprinkle your reserved M&M’s and chocolate chips on top. Bake for 30-35 minutes if you’re using the 9×13 pan, or about 20 minutes for a 15×10 pan, until the top is just golden brown and set. When you gently press the surface, it should give slightly but not feel wet or doughy. Cool completely in the pan before slicing. I promise, patience here pays off for the best clean cuts.

How to Serve M&M Cookie Bar Recipe

Garnishes

I often keep it simple and top a freshly cut bar with a tiny pinch of flaky sea salt—it brings out the chocolate and M&M flavors so well. Another favorite is serving it alongside a small scoop of vanilla ice cream for an extra indulgent treat.

Side Dishes

This recipe pairs wonderfully with a cold glass of milk or a hot cup of coffee or tea. For parties, I like to set out fresh fruit, like strawberries or sliced apples, as a refreshing counterbalance to the rich sweetness of the bars.

Creative Ways to Present

For birthdays or holiday gatherings, I’ve decorated the top with themed M&M’s and piped on a bit of frosting around the edges to add color and flair. Cutting these into small bite-sized squares also makes these bars perfect for potlucks and kids’ lunchboxes.

Make Ahead and Storage

Storing Leftovers

After the bars cool, I store them in an airtight container at room temperature for up to 3 days. They stay soft and delicious with no loss of flavor. If my family could eat the whole batch in one day, I’d challenge them—but leftovers definitely hold up well.

Freezing

These bars freeze beautifully! I wrap slices individually in plastic wrap, then place them in a freezer-safe bag for up to 3 months. When I want one, I just thaw it on the counter for about an hour before enjoying.

Reheating

If you want warm bars, microwaving a slice for 10 to 15 seconds does the trick perfectly without overdoing it. You’ll get melty chocolate and that fresh-baked feel again in seconds.

FAQs

Final Thoughts

I absolutely love how this M&M Cookie Bar Recipe turns out every single time, and I’m so excited to share it with you. It’s one of those recipes that feels like a warm hug from the oven—familiar, bright, and irresistible. Whether you’re baking for your family, hosting friends, or just treating yourself, these bars always hit the spot. Give it a try, and I promise you’ll be hooked, just like me!

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