Cake Mix Cookie Bars Recipe

If you’re craving a quick, no-fuss dessert that still feels fun and a little indulgent, these cake mix cookie bars are perfect! Made with just a handful of ingredients—most of which you probably have in your pantry—they come together in no time and taste incredible. The combination of buttery, chewy goodness with the colorful crunch of M&M’s makes these bars a hit with kids and adults alike. Plus, they’re versatile enough to dress up or keep simple, depending on your mood!

this RECIPE

A sweet memory with cookie bars

I remember the first time I made these cake mix cookie bars; it was a last-minute treat idea for a movie night with friends. I had been racking my brain for something easy but crowd-pleasing and stumbled upon a box of yellow cake mix in my pantry. With a little creativity and some M&M’s I had on hand, these bars came to life. As soon as they came out of the oven, the entire house filled with the warm, comforting aroma of vanilla and chocolate. By the end of the movie, there wasn’t a crumb left, and I knew I’d found a new go-to dessert for casual gatherings!

The cake mix cookie bar origin story

Cake mix cookie bars are part of a long tradition of “shortcut baking,” which gained popularity in the mid-20th century when boxed cake mixes first became widely available. Home bakers realized they could transform these mixes into more than just cakes. Cake mix cookies, bars, and even brownies became a hit as people found ways to get creative while saving time. These bars, in particular, take the essence of a classic cookie but with a soft, dense texture more like a brownie—perfect for when you want the best of both worlds.

Let’s talk ingredients: cake mix, butter, eggs, and M&M’s

Each ingredient in these cake mix cookie bars serves a specific purpose, making this dessert both easy and delicious.

• Yellow cake mix: This is the foundation of the bars, giving them a sweet, vanilla flavor and that soft, chewy texture we all love. You can swap the yellow cake mix for chocolate or even a funfetti mix if you want to try different flavors!
• Butter: Melted butter adds richness and moisture, making the bars wonderfully soft. For a slightly different flavor, you could use melted coconut oil instead, though it will give a subtle coconut taste.
• Eggs: The eggs help bind the mixture and give the bars a bit of lift. If you’re out of eggs, try substituting each egg with 1/4 cup of unsweetened applesauce—though it may make the bars a tad softer.
• M&M’s: These little candies add a pop of color and a sweet, chocolatey crunch. Feel free to get creative here—chocolate chips, mini marshmallows, or chopped nuts could work well if you’re in the mood for something different.

Kitchen gear you’ll need (and what you can skip)

To whip up these bars, you don’t need much—just the basics!

• Mixing bowl: A medium-sized mixing bowl will do the trick for combining everything. If you don’t have a dedicated mixing bowl, a large soup pot can double as one in a pinch.
• Spatula: A rubber spatula is great for spreading the sticky dough evenly into the pan. If you don’t have one, the back of a large spoon works too.
• 9×9 baking pan: This is ideal for getting the right thickness. If you don’t have a 9×9 pan, an 8×8 pan will work too, but you might need to add a few extra minutes to the baking time.
• Parchment paper: Lining the pan with parchment paper makes removing the bars super easy and keeps them from sticking. If you’re out of parchment paper, give the pan a good coating of non-stick spray.

Step-by-step: making the perfect cookie bars

Let’s make these cookie bars together! Here’s everything you need to know, along with a few tips I’ve picked up along the way.

1. Preheat the oven to 350°F. This way, it’ll be nice and hot by the time you’re ready to bake. Grease your 9×9 baking pan with non-stick spray and line it with parchment paper, letting a bit of paper hang over the edges for easy lifting later.
2. Mix the ingredients. In a medium mixing bowl, combine the cake mix, melted butter, and eggs. Stir until you get a thick, sticky dough. It might look a little too thick, but that’s exactly what you want! If your dough feels too dry, you can add a tablespoon of water to help it come together.
3. Fold in the M&M’s. Pour the M&M’s into the dough and give it a few stirs to distribute them evenly. I sometimes set a few aside to sprinkle on top for an extra pop of color after baking.
4. Spread the dough in the pan. Using a spatula (or the back of a spoon), spread the dough evenly in the prepared pan. It’ll be thick, so take your time to get it into the corners.
5. Bake for 25-30 minutes. Pop the pan in the oven and bake until the bars are golden brown and slightly crisp on top. Start checking around the 25-minute mark. They should still be a little soft in the center when you pull them out—don’t worry, they’ll firm up as they cool!
6. Cool and cut. Use the parchment paper to lift the bars out of the pan and onto a cutting board. Let them cool for at least 10 minutes before slicing; this helps keep them from crumbling.

Variations to make these cookie bars your own

There’s so much you can do with these cake mix cookie bars to make them just the way you like!

• Chocolate cake mix: Swap out the yellow cake mix for chocolate to create a rich, brownie-like bar. Add white chocolate chips or peanut butter chips for extra flair.
• Peanut butter M&M’s: If you’re a peanut butter fan, use peanut butter M&M’s or even add a swirl of peanut butter into the batter before baking.
• Seasonal add-ins: Try using holiday-themed M&M’s for a festive touch.
• Healthier version: Substitute half the butter with unsweetened applesauce to reduce fat. You could also mix in some oats or chia seeds for a bit of added fiber.
• Nutty twist: Add a handful of chopped walnuts or pecans for a nice crunch and some extra depth in flavor.

How to serve these cookie bars (and make them look amazing)

These bars are pretty enough on their own, but a little extra presentation can make them shine!

• Plating: Arrange the bars on a platter with a sprinkle of powdered sugar on top for a touch of elegance. You could also drizzle some melted chocolate or caramel sauce over them.
• Add a scoop of ice cream: Serve each bar with a scoop of vanilla ice cream on the side, and maybe a drizzle of chocolate syrup for that classic cookie-and-ice-cream vibe.
• Garnish with extra M&M’s: Right after baking, press a few extra M&M’s on top of the bars to add a pop of color—especially fun for kids!

Drinks to pair with your cookie bars

Looking for something to sip while you enjoy these bars? Here are a few ideas:

• Milk: There’s nothing like a cold glass of milk with a chewy, sweet cookie bar. For a twist, try flavored milk like chocolate or strawberry.
• Hot chocolate: Especially cozy in cooler months, a mug of hot chocolate with a dollop of whipped cream makes a perfect pairing.
• Iced coffee: If you’re serving these bars in the afternoon, an iced coffee or cold brew balances the sweetness perfectly.
• Herbal tea: Chamomile or mint tea can provide a soothing, lighter option to sip alongside these rich bars.
• Fruit smoothie: For a refreshing contrast, a berry smoothie or even a classic strawberry-banana smoothie can be a delightful, fruity companion.

Storing and reheating your bars

If you have any leftovers (though it’s unlikely!), here’s how to keep them fresh:

• Storage: Store the bars in an airtight container at room temperature for up to 3 days. If you’d like them to last longer, keep them in the fridge, where they’ll stay fresh for about a week.
• Freezing: These bars freeze well! Wrap each one individually in plastic wrap, then store in a freezer-safe bag for up to 3 months. Thaw at room temperature or pop in the microwave for a quick warm-up.
• Reheating: For that freshly-baked warmth, reheat the bars in the microwave for 10-15 seconds. They’ll get soft and gooey all over again!

Adjusting the recipe for more (or fewer) servings

Need to make a bigger batch? You can easily double the recipe and bake it in a 9×13 pan. If you want a smaller batch, you can halve the ingredients and use a loaf pan—just check for doneness a few minutes earlier.

Common questions about cake mix cookie bars

Q: Can I use a different type of cake mix?
A: Absolutely! Chocolate, funfetti, or even spice cake mix works well. Each brings a unique flavor to the bars.

Q: What if I don’t have M&M’s?
A: Chocolate chips, crushed Cookies, or even dried fruit can be great substitutes!

Q: Can I make these gluten-free?
A: Yes! Use a gluten-free yellow cake mix, and you’re good to go.

Q: Why are my bars too crumbly?
A: They may be overbaked. Try checking a few minutes earlier next time to keep them moist.

Q: How do I know when they’re done?
A: They should be golden on top and slightly soft in the middle. They’ll firm up as they cool.

Enjoy baking these cake mix cookie bars, and feel free to get creative with your own twist! Whether you’re serving them for a party or just indulging in a treat, they’re bound to be a hit.

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