Mint Chocolate Brownie Cupcakes (Easy Doctored Brownie Mix Hack)

Turn a simple brownie mix into decadent mint chocolate brownie cupcakes topped with mint fudge buttercream and Andes chips. Easy, rich, and perfect for mint chocolate lovers!

If you love brownies and cupcakes, these mint chocolate brownie mix cupcakes are the perfect mash-up. Made with a simple boxed brownie mix, they bake up rich, chocolatey, and slightly fudgy—somewhere between a cupcake and a brownie.

The real star, though, is the mint fudge buttercream, made with cocoa, powdered sugar, butter, and melted mint chocolate chips. Top it all off with Andes mint chips and you’ve got a dessert that feels bakery-worthy but is incredibly easy to make.

According to my granddaughter Jenna, these cupcakes are “the most amazing thing I’ve ever tasted.” And honestly? I have to agree.

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Why These Brownie Mix Cupcakes Work

As the baker behind Out of the Box Baking, I’ve spent years experimenting with ways to transform simple mixes into something extraordinary. Don't believe me? You'll want to check out my Cake Mix Creations post for some of my favorite ideas!

Boxed mixes are reliable, affordable, and easy to customize, which makes them perfect for creative baking projects—especially when baking with kids. I've used mixes for cakes, cupcakes, cookies, scones, muffins, and so much more!

Impromptu Baking Sessions are So Fun!

This particular recipe grew out of a spontaneous baking session with my granddaughter Jenna, who came over with her dad, (who had gracious agreed to put together my new grill).

We wanted cupcakes but when I saw the brownie mix in my cupboard, I went to Plan B. I knew that I had Andes mint chocolate chips in the fridge and a plan began to hatch.

With a few small adjustments—extra eggs for structure, milk for moisture, and mint chips for flavor—we created cupcakes that are fudgy like brownies but light enough to frost. The result is a dessert that’s simple, delicious, and kid-approved.

More about that later.

Mint Chocolate Brownie Cupcake Ingredients

You will find a full printable recipe card at the bottom of this post but here's a quick look at what you're going to need to make these cupcakes. These are simple ingredients you might already have on hand in your pantry or fridge.

For the Brownie Cupcakes

• 1 box chocolate fudge brownie mix
• 3 large eggs
• ½ cup oil
• ¼ cup milk
• ½ cup mint chocolate chips (I prefer Andes for this recipe)

For the Mint Fudge Buttercream

• 2 sticks (1 cup) butter, softened
• ¼ cup cocoa powder
• 3–4 cups powdered sugar
• ½ cup mint chocolate chips
• 1 tablespoon cream

For Topping

• Andes mint baking chips or chopped Andes candies

How to Make Mint Chocolate Brownie Cupcakes

These come together so easily! My granddaughter did most of the work, herself. We didn't even use a mixer for the cupcakes. Just mixed 'em up in a bowl. Here's how you're going to do it.

1. Prepare the Oven and Pan

Preheat your oven to 350°F. Line a standard 12-cup muffin pan with cupcake liners.

2. Mix the Batter

In a large mixing bowl, combine: brownie mix, eggs, oil, milk. Stir until smooth and glossy. Fold in the mint chocolate chips. The batter will look rich, thick, and shiny—almost impossible to resist sneaking a taste!

3. Fill the Cupcake Liners

Scoop batter into the cupcake liners, filling them about ⅔ full.

4. Bake

Bake at 350°F for about 18 minutes. The cupcakes are ready when the tops look set and slightly crackly and a toothpick inserted comes out with moist crumbs but no wet batter. They will look darker and richer than traditional cupcakes, almost like mini brownies.

5. Cool Completely

Allow the cupcakes to cool fully before frosting.

Mint Fudge Buttercream

This frosting is thick, chocolatey, and full of mint flavor. Here's how you're going to make it.

1. Melt the Mint Chocolate

In a small bowl, melt ½ cup mint chocolate chips and 1 tablespoon cream. Microwave in short bursts, stirring until smooth. Set aside to cool slightly.

2. Make the Frosting

In a mixing bowl, beat together softened butter and cocoa powder. Gradually add powdered sugar until thick and fluffy.

3. Add the Mint Chocolate

Pour the melted mint chocolate mixture into the frosting and beat until smooth. The frosting will be dense, rich, and intensely chocolate-minty.

4. Frost the Cupcakes

Once the cupcakes are fully cooled, spread or pipe the frosting onto each cupcake. Sprinkle Andes mint chips on top for extra flavor and texture.

Store cupcakes in an airtight container. They will be good at room temperature up to 2 days and in the refrigerator up to 5 days. Bring to room temperature before serving for the best texture.

What to Expect

These cupcakes are not like traditional fluffy cupcakes. Instead, they land perfectly in the middle:

• richer than cake
• lighter than brownies
• deeply chocolatey
• loaded with mint flavor

The frosting is thick, fudgy, and decadent, almost like a mint chocolate truffle filling. (Yum!) The luscious texture is similar to something you would find in my Doctored Brownies and Bars recipes.

Baking with Jenna

My granddaughter Jenna helped with every step of this recipe—and she had a very strong opinion about the final result. In her words:

“They are the most amazing thing I’ve ever tasted!”

She also reported that the batter was so shiny and delicious that we had to keep a close eye on it to make sure too many fingers didn’t sneak in for a taste.

Honestly, baking together in the kitchen might have been the best part of all.

Variations

You know me: I love to mix things up! Maybe next time I'll do this, instead:

Triple Chocolate: Stir ¼ cup chocolate chips into the batter along with the mint chips.

Mint Drizzle: Drizzle melted chocolate over the frosted cupcakes.

Peppermint Chips: Sprinkle them on top for extra color. They will be perfect for Christmas, like my Double Dark Chocolate Peppermint Cookies, (which are so delicious)!

Other Doctored Mixes to Enjoy

If you enjoy transforming boxed mixes into something special, you’ll also want to check out my Doctored Brownies and Bars, where I share simple ways to upgrade brownie mixes into bakery-style treats.

I've got a growing list of cake mix cupcakes you're sure to enjoy. It's so simple to turn a box of mix into something that tastes like it came from a high-end bakery!

If Doctored Mixes are your thing you'll want to check out the following posts:

• How to Doctor a Cake Mix
• 80 Doctored Cake Mix Recipes
• 40 Boxed Cake Mix Secrets
• Jazz up a Boxed Cake Mix, 12 Easy Hacks

Questions People are Asking

Can you turn brownie mix into cupcakes?

• Yes! Brownie mix works beautifully in cupcake form. Simply prepare the batter as directed and bake it in lined cupcake tins. The result is a dessert that’s slightly fudgy like a brownie but structured enough to frost.

Why add milk to brownie mix?

• Adding a small amount of milk helps lighten the batter slightly, creating a texture that works better for cupcakes rather than dense brownies.

Do brownie cupcakes rise like cake?

• Not quite. They rise slightly but remain denser and more chocolate-rich than traditional cupcakes.

Final Thoughts

This recipe proves something I’ve always believed: A simple box mix can become something truly special with a little creativity. (This site is called "out of the box" for a reason! I don't just love cake mixes, I love to be creative in the kitchen!)

When you add mint chocolate and a grandkid taste-tester to the process, it becomes even better. Don't believe me? Ask Jenna!

Thanks for stopping by, friends. I hope you enjoy this recipe as much as we did! If so, please leave a comment or review.

Before you go, why not pin some photos to your Pinterest boards?

May the God of hope fill you with all joy and peace as you trust in him, so that you may overflow with hope by the power of the Holy Spirit.

Romans 15:13