This post may contain affiliate links.
Mint Brownies are the triple decker showstopper of the bar dessert world, fudgy double chocolate brownies with a full layer of mint Oreos baked inside, topped with fluffy green peppermint frosting and a pourable milk chocolate fudge. I made a pan for a weekend movie night and they out muscled our beloved lemon brownies for first tray emptied.
Three layers sounds fancy, but each one is genuinely easy and two of them barely count as cooking.
Mint Brownies Quick Look
- 🕒 Prep Time: 30 minutes
- 🌡️ Cook Time: 23 minutes
- ⏳ Total Time: 1 hour 53 minutes
- 🍽️ Serving: 24 small servings
- ⚡ Calories: 551kcal
- 🌶️ Flavor Profile: Deep double chocolate with cool peppermint cream
- ✋ Difficulty: Easy, the same layer and chill rhythm as our chocolate chip cookie bars
Quick Answer
Make a double chocolate brownie batter with melted chocolate, cocoa, and chocolate chips, spread half in a 9×13 pan, layer on 24 mint Oreos, cover with the remaining batter, and bake at 350 degrees for 20 to 23 minutes. Once cool, spread on a whipped peppermint buttercream tinted green and chill 1 hour, then pour over a quick fudge frosting made from milk chocolate chips, butter, and sweetened condensed milk. Chill until set and slice.
Jump to:
Why This Recipe Works
Click to see the technique science
- A whole Oreo layer bakes inside. The 24 mint Oreos soften into a fudgy cookie stratum between the brownie layers, a surprise crunch of mint in every square.
- Melted chocolate bar plus cocoa is double chocolate for real. The bar brings fudginess while the cocoa deepens the flavor, so the base can stand up to two frosting layers.
- The frosting chill sets each stripe. An hour in the refrigerator firms the mint layer before the warm fudge goes on, which is why the three layers stay picture perfect when sliced.
- Condensed milk makes foolproof fudge. Milk chocolate chips, butter, and sweetened condensed milk melt into a pourable fudge that sets glossy, no candy thermometer involved.
- Peppermint extract beats mint extract. Peppermint reads as candy cane cool and clean, while generic mint extract can drift toward toothpaste.
- They slice into 24 rich little squares. These are tall, dense bars, small squares mean the pan feeds a crowd and nobody hits sugar overload.
Why You’ll Love This Recipe
- Three dramatic layers from one 9×13 pan, they look like a bakery case and slice like a dream.
- The mint Oreo layer inside is a genuine surprise moment, people always ask how it got there.
- They are a make ahead hero since the pan needs chill time anyway, just like our Butterfinger brownies, the fridge does the finishing.
Key Ingredients
Three short layers, and the ingredient list splits neatly between them.
- Mint Oreos: Twenty four cookies make the hidden middle layer, they soften as the brownies bake into fudgy mint pockets.
- Semi sweet chocolate bar and chocolate chips: The melted bar makes the batter fudgy, the chips stud it with melty pockets.
- Peppermint extract: The cool, clean mint flavor for the green frosting layer, a little goes a long way.
- Sweetened condensed milk: The secret to the milk chocolate fudge topping, it melts with the chips into a pourable frosting that sets glossy.
- Green food coloring: Optional but fun, a few drops turn the mint layer that classic grasshopper green.
See recipe card for exact quantities.
Variations and Substitutions
The triple layer formula loves a costume change.
- Skip the food coloring for an elegant white mint layer, or go pink with crushed candy canes on top for Christmas.
- Swap the mint Oreos for regular Oreos and the peppermint for vanilla extract for a cookies and cream version.
- Use dark chocolate chips in the fudge topping if milk chocolate runs too sweet for your crowd.
- Make it a St. Patricks Day centerpiece with a sprinkle of green sanding sugar over the fudge before it sets.
How to Make Mint Brownies
- Preheat the oven to 350 degrees and line a 9×13 pan with parchment or greased foil. Mix the flour, cocoa powder, baking soda, salt, and both sugars in a stand mixer on low. Microwave the butter and broken up chocolate bar in a large bowl, 1 minute at a time with rests, until melted and smooth, then stir in the vanilla and cool 5 minutes.
- Add the eggs to the dry ingredients one at a time and beat on medium for 2 minutes. On low, slowly pour in the melted chocolate and mix until just incorporated, then fold in the chocolate chips.
- Scoop half of the brownie batter into the pan and smooth it out, then layer the mint Oreos over the top in rows.
- Top with the remaining batter, smooth it over the cookies, and bake 20 to 23 minutes until the top is shiny and set. Cool completely on a wire rack.
- For the mint layer, whip the butter for 2 minutes, add the powdered sugar a little at a time, then the milk, and whip 2 more minutes on high. Beat in the peppermint extract and green food coloring, spread over the cooled brownies, and refrigerate 1 hour.
- For the fudge topping, layer the butter, milk chocolate chips, and sweetened condensed milk in a microwave safe bowl. Heat 1 minute, rest 1 minute, and stir, repeating once or twice until smooth. Pour over the mint layer, smooth carefully, and refrigerate until set before slicing.
Recipe Tips & Tricks
- Line the pan with an overhang. Lifting the whole slab out makes slicing the three layers clean and easy.
- Cool the melted chocolate 5 minutes before adding it. Pouring it in hot can scramble the eggs in the batter.
- Do not overbake, shiny and set is done. The brownies keep cooking in the hot pan and overbaking costs you the fudgy middle.
- Chill between every layer. Warm brownies melt the mint frosting and warm mint frosting swirls into the fudge, the refrigerator keeps the stripes sharp.
- Smooth the fudge gently. Pour it over the chilled mint layer and nudge it to the edges with an offset spatula without pressing down.
- Slice with a hot dry knife. Run the blade under hot water and wipe between cuts for those clean bakery stripes, 24 small squares is the sweet spot.
Serving Ideas and Suggestions
These are the dessert tray royalty for St. Patricks Day, Christmas, and any party that needs a wow, set them out with our pecan pie brownies and watch the great bar debate begin.
Serve a square slightly chilled with a scoop of vanilla or our no churn cookie dough ice cream, the cold mint against the fudge is unreasonably good.
For a chocolate lover gift box, pair a few squares with our chocolate covered peanut butter pretzels, they survive the trip beautifully.
Store them covered in the refrigerator up to 5 days, the layers actually taste better on day two. They freeze well too, slice first and thaw squares in the refrigerator overnight.
Mint Brownies FAQs
Three layers, a double chocolate brownie base with a full layer of mint Oreos baked inside, a whipped peppermint buttercream tinted green, and a milk chocolate fudge topping made with sweetened condensed milk. Rich pantry basics doing very dramatic work.
Yes, both frosting layers are happiest chilled. Refrigerate the pan until the fudge sets before slicing, and store leftovers covered in the refrigerator up to 5 days. Let squares sit out 10 minutes before serving for the fudgiest texture.
You can shortcut the base with a 9×13 boxed brownie mix, layer the mint Oreos in the middle the same way, and the frosting layers do not change. The from scratch double chocolate base is noticeably fudgier though, and it is one bowl.
A whipped peppermint buttercream, softened butter beaten with powdered sugar and a splash of milk, flavored with peppermint extract and tinted with green food coloring. The color is optional, the frosting tastes exactly the same in white.
Chill the pan until the fudge topping is fully set, lift the slab out by the parchment, and slice with a long knife run under hot water and wiped dry between cuts. Cold bars plus a hot clean blade equals sharp three layer stripes.
Yes, they freeze beautifully for up to 3 months. Slice them first, layer squares between parchment in an airtight container, and thaw overnight in the refrigerator. The mint and fudge layers hold their looks through the thaw.
Made these Mint Brownies? Leave a comment and a star rating below, I would love to hear if anyone found the hidden Oreo layer before the first bite!
If layered brownies are your love language, our cheesecake brownies belong on your list.
Our from scratch German chocolate brownies bring the coconut pecan magic.
Mint chocolate fans, my chocolate covered Ritz crackers take 30 minutes and zero oven time.
Mint lovers, my swirled peppermint cheesecake belongs on your holiday table.
Come St. Patrick’s Day, my baileys brownies take over the dessert table.
Bake a batch of my chocolate m&m cookies for the lunchbox win.
Match them with my baileys cupcakes for the full St. Patrick’s Day spread.
Mint Brownies
Ingredients
- 1 ½ cups all-purpose flour packed
- ¾ cup unsweetened cocoa powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- 1 cup granulated sugar
- 1 cup brown sugar packed
- ¾ cup butter
- 6 ounces semi-sweet chocolate bar
- 1 ½ teaspoon vanilla extract
- 3 large eggs
- 2 cups semi-sweet chocolate chips
- 24 mint oreo cookies
Mint frosting:
- ½ cup unsalted butter room temp
- 2 cups powdered sugar
- 2 Tablespoon milk
- 1 ¼ teaspoon peppermint extract
- green food coloring optional
Milk Chocolate Fudge Frosting:
- 2 Tablespoons butter
- 2 cups milk chocolate chips
- 14 ounces sweetened condensed milk
Instructions
- Preheat the oven to 350°F degrees. Line 9×13 baking pan with foil and spray with non-stick cooking spray or line with parchment paper.
- Place the flour, cocoa powder, baking soda, salt, and both sugars into the bowl of a stand mixer with the paddle attachment. Mix on low until combined.
- In a microwave-safe bowl, add in the butter and break up the semi-sweet chocolate bar, and place on top. Heat on High in the microwave for one minute and stir. Heat for an additional minute in the microwave, let sit for one minute and stir to combine. Repeat only if necessary, everything should be melted. Stir in the vanilla and let sit on the counter for 5 minutes to cool.
- While the mix is cooling, add the eggs to the mixer bowl with the dry ingredients one at a time. When all the eggs are added, beat on medium speed for two minutes. Turn the mixer down to low and slowly pour in the liquid mix, beat until fully incorporated but do not over mix.
- Add the chocolate chips and fold them into the brownie mix.
- Scoop half of the brownie mix into the pan and smooth it out with a spatula.
- Layer on the mint oreo cookies.
- Then top with remaining brownie batter, and smooth out.
- Bake for 20-23 minutes until the top is shiny and set, take it out of the oven, and let cool on a wire rack.
Mint Frosting:
- With a hand mixer, whip the butter on medium speed in a medium-sized bowl for 2 minutes. Add in the powdered sugar a little at a time until fully combined. Add in the milk and whip for an additional 2 minutes on high speed.
- Add in the peppermint extract and food coloring to the color you want. Whip one additional minute.
- Spread on the mint frosting once the brownies have cooled. Place in the refrigerator to set for one hour.
Milk Chocolate Fudge Frosting:
- Place the butter in the bottom of a microwave-safe bowl. Place the milk chocolate chips on top of the butter.
- Pour the sweetened condensed milk on top of the chocolate. Heat in the microwave on high for 1 minute. Let sit for 1 minute and stir.
- Repeat again and a third time only if necessary. The mixture should combine fully and be melted.
- Pour on top of the fudge frosting and carefully smooth it out. Place back in the refrigerator until ready to serve to let the frosting set. Enjoy!
Notes
- Make sure you use unsweetened cocoa powder and not dutch process.
- We like to use high quality chocolate chips for this recipe.
- Different types of mint cookies can be found at different grocers, you don’t need the oreos.
- These can be frozen, see my storage tips above!
- These need to be refrigerated as well because you don’t want the frosting to melt off.
- Make sure your brownies are fully cooled before you frost them.
- If you want you can use a boxed brownie mix.
Nutrition
Love This Recipe?
Follow @ThisSillyGirlsKitchen on Instagram and @danadevolk on Pinterest for more!
This look yummy and dangerous! I will have to steal some thin mints from my husband to make them. I found you on Work it Wednesday link party.
Yum! These look devine! I am pinning right now. I have no doubt that my kids will choose this as the next treat we will make 🙂
Thank you so much for sharing on the Brag About It Link Party!
Your brownies look very tasty, I love the mint and chocolate combinations!
I love Joann Fluke! I stumbled across one of her books in a thrift store and have been hooked. I just got a gift card to a local bookstore, and couldn’t think what to get, but now I know! It’s time for another mystery full of recipes!
Thanks for sharing these on Weekend Bites 🙂
my favorite type of brownie? These! a childhood friend’s mom would make a similar brownie.
Came across this post on Pinterest and whew, these are a TREAT! Absolutely can’t wait to make these! I pinned this recipe 🙂
Also, love your blog! Glad to be your newest follower!
I love your take on the brownies, what’s not to like with brownies. I also love Joanne Fluke. I have read all of her books except for this one. I get so hungry when I read her books. I have tried several of her recipes and they are always great.
Cream cheese brownies are awesome and one of my favorites.
Enjoy the book.
Bev
Thin mints in brownies!? Sign me up!
These look really good… very special for the sweet tooth. 🙂
These look absolutely wonderful. I love chocolate! I’m on a diet right now, these will be something to look forward to. Thanks so much for sharing. New follow through the Weekend Re-Treat Link Party. I would love for you to come link up at the Feather Your Nest Friday Link Up Party tomorrow morning at 9:00 am MST.
Lory xo
http://www.therobinsnestdesigns.com
Wow! These sound over-the-top amazing!