Last weekend, my family joined a big neighborhood picnic at the park. Everyone brought something to share, and I swear the dessert table was like a rainbow—pies, cupcakes, brownies, you name it. I decided to bring something easy to slice and pass around, but still colorful enough to catch the kids’ eyes. That’s when I turned to my trusty M&M Cookie Bars. By the time I carried the pan over, I had three moms asking for the recipe just from the smell alone.

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This recipe straddles that sweet spot between playful and practical. You don’t need to fuss with individual cookies, and the bars bake up evenly in one pan—perfect for busy weeknights or gatherings when time is short. My daughter helped press the dough into the pan, and my son carefully sprinkled extra M&M’s on top (with a few sneaky taste-tests, of course). By the end of the day, my plate came back completely empty, which is always the best compliment.

These bars have that buttery chew of a cookie, pockets of melted chocolate chips, and bursts of candy crunch from the M&M’s. They travel well, slice cleanly, and please both kids and adults. Honestly, they’re the kind of recipe that feels like a lifesaver when you’ve got a party, potluck, or even just a Monday craving.

Short Description

Soft, buttery cookie bars packed with chocolate chips and colorful M&M’s. Easy to make in one pan, sliceable for sharing, and always a crowd favorite.

Key Ingredients

1 cup (2 sticks) unsalted butter, softened
1 cup packed light brown sugar
½ cup granulated sugar
2 large eggs, at room temperature
1 tablespoon pure vanilla extract
2 ¾ cups all-purpose flour
1 teaspoon cornstarch
1 teaspoon baking soda
½ teaspoon fine sea salt
1 ½ cups milk chocolate M&M’s candies, divided
1 cup semi-sweet chocolate chips

Tools Needed

Stand mixer or hand mixer
Mixing bowls
9×13 inch metal baking pan
Parchment paper
Measuring cups and spoons
Spatula
Wire rack

Cooking Instructions

Step 1: Prep and Preheat
Preheat oven to 350°F (175°C). Grease a 9×13 inch metal baking pan and line it with parchment paper, leaving a 2-inch overhang on the sides for easy lifting.

Step 2: Cream Butter and Sugars
In a stand mixer or with a hand mixer, beat softened butter, brown sugar, and granulated sugar together on medium speed for 2–3 minutes until light and fluffy.

Step 3: Add Eggs and Vanilla
Beat in the eggs one at a time, mixing well after each. Stir in vanilla until just combined.

Step 4: Mix Dry Ingredients
In a separate bowl, whisk flour, cornstarch, baking soda, and salt.

Step 5: Form the Dough
Gradually add dry ingredients to wet mixture on low speed until only a few flour streaks remain. Fold in 1 cup of M&M’s and all chocolate chips with a spatula. If dough feels sticky, add 1 tablespoon flour at a time.

Step 6: Press and Top
Spread dough evenly into prepared pan using greased hands or the back of a measuring cup. Sprinkle remaining ½ cup M&M’s on top and gently press them in.

Step 7: Bake
Bake 22–26 minutes, until edges are firm and top is lightly golden. The center should look slightly soft—that’s the secret to chewy bars.

Step 8: Cool and Slice
Cool completely in the pan on a wire rack. Lift the slab out using parchment overhang and cut into squares or rectangles.

Why You’ll Love This Recipe

Chewy and Gooey: A perfect mix of soft cookie texture with melty chocolate.

Party-Perfect: Easy to slice, pack, and share.

Colorful Appeal: M&M’s add crunch and bright pops of color.

Kid-Friendly: Great for little helpers in the kitchen.

Make-Ahead Friendly: Can be baked the night before and stored for the next day.

Mistakes to Avoid & Solutions

Overbaking: Bars may turn dry. Solution: Remove when edges are golden but center looks slightly soft.

Skipping Parchment: Without parchment, bars may stick. Solution: Always line the pan with an overhang.

Uneven Spreading: Leads to uneven baking. Solution: Use a spatula or measuring cup to press the dough flat.

Too Much Mixing: Can make the bars tough. Solution: Stop mixing once flour streaks disappear.

Crowding M&M’s on top: They may burn. Solution: Press gently so candies sink slightly into dough.

Serving and Pairing Suggestions

Serve warm with a scoop of vanilla ice cream for a sundae twist.

Pair with a glass of cold milk for classic comfort.

Add them to a dessert buffet alongside brownies and blondies.

Cut into small bites for party platters or school lunches.

Storage and Reheating Tips

Store bars in an airtight container at room temperature for up to 5 days.

Freeze cooled bars in a freezer bag for up to 2 months. Thaw at room temperature.

For warm bars, reheat individual pieces in the microwave for 10–12 seconds.

FAQs

1. Can I use different flavors of M&M’s?
Yes, peanut, peanut butter, or seasonal varieties work well.

2. Can I bake this in a glass pan instead of metal?
You can, but increase bake time by about 3–5 minutes. Metal pans give more even results.

3. Do I need to chill the dough?
Not for this recipe—straight into the oven is fine.

4. How do I cut clean squares?
Wait until bars are completely cool, then use a sharp knife wiped clean between cuts.

5. Can I reduce the sugar?
You can reduce granulated sugar by 2–3 tablespoons without affecting texture much.

Tips & Tricks

Add a sprinkle of flaky sea salt on top before baking for a sweet-salty finish.

Reserve a handful of chocolate chips to press on top for a bakery-style look.

Don’t skip cornstarch, it helps keep the bars soft and chewy.

If making for a crowd, double the recipe and bake in two pans.

Recipe Variations

Peanut Butter M&M Bars: Replace ½ cup butter with ½ cup creamy peanut butter and use peanut M&M’s.

Holiday Bars: Use red and green M&M’s at Christmas, or pastel ones at Easter.

Oatmeal M&M Bars: Swap 1 cup flour for 1 cup rolled oats for a heartier texture.

Dark Chocolate Lovers: Replace milk chocolate M&M’s with dark chocolate ones and swap chips for chopped dark chocolate chunks.

Final Thoughts

These M&M Cookie Bars feel like the kind of recipe that makes life easier while still delivering big smiles. They’ve become my secret weapon when I need something reliable and festive, especially for potlucks and birthdays. These bars don’t require scooping or chilling—just mix, press, bake, and slice. They’re playful enough to delight kids but not too sweet for adults.

My family keeps asking for them, which tells me they’ve earned a permanent place in our rotation. Next time you need a cheerful, no-fuss dessert, these cookie bars are worth turning on the oven for. They’re colorful, chewy, and just plain happy-making.

M&M Cookie Bars