This Thin Mint Sheet Cake recipe will satisfy your Girl Scout Thin Mint Cookie cravings anytime of the year! Indulge your taste buds with this decadent treat that combines the classic flavors of thin mint cookies (Girl Scout Thin Mint Cookies, Goodie Girl Gluten Free Mint Cookies, or Oreo Mint Cookies). This recipe is made with a mint cookie crust & a moist & decadent mint chocolate cake that is topped off with chocolate ganache & a creamy mint cookie frosting. This cake is perfect for anyone with a sweet tooth and a love for all things minty.
WHAT YOU NEED TO MAKE THIS THIN MINT CHOCOLATE CAKE
- Chocolate Cake Box Mix: Any brand of chocolate cake box mix will do.
- Pure Vanilla Extract: Gives flavor! I get my favorite pure vanilla extract from Costco.
- Mint Extract: You can also use peppermint extract.
- Butter: Melted. I recommend using unsalted butter because you are able to control the amount of salt you want.
- Buttermilk: Make sure you bring the milk to room temperature. Avoid lower fat or nonfat milks. Milk with fat will give you the best flavor and add moisture to the cake. If you don’t have buttermilk, you can make a DIY sour milk substitute. Add 2 teaspoons of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1 cup. (In a pinch, lower fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
- Sour Cream: Makes cakes moist! Make sure sour cream is at room temperature. I would suggest removing from the fridge an hour or so ahead of time.
- Avocado Oil: Since cocoa powder is a particularly drying ingredient this cake needs oil for suitable moisture. You can also use vegetable oil, canola oil or melted coconut oil.
- Unsweetened Cocoa Powder: Use natural cocoa powder in the cake, not dutch-process.
- Eggs: Make sure you bring the eggs to room temperature so they can effortlessly mix into the batter without over mixing.
- Girl Scout Thin Mint Cookies: You’ll need 2 boxes of Girl Scout Thin Mint Cookies. If you can’t get your hands on Girl Scout Cookies you can substitute with a package of Oreo Mint Cookies or Goodie Girl Gluten Free Mint Cookies (you’ll need at least 3 boxes total for this recipe).
- Edible Glitter (optional): I used Fancy Sprinkles edible gold glitter.
WHAT INGREDIENTS YOU NEED TO MAKE THIN MINT CHOCOLATE BUTTERCREAM
- Butter: I recommend using unsalted butter because you are able to control the amount of salt you want especially when making the frosting. Be sure to bring the butter to room temperature. I always take mine out a couple hours before I want to bake. It must be soft enough so your finger leaves a dent when pressing it. If you forgot to take your butter out to come out to room temperature you can also zap it in the microwave for about 20 seconds. Do not melt the butter completely.
- Girl Scout Thin Mint Cookies: If you can’t get your hands on Girl Scout Cookies you can substitute with Oreo Mint Cookies or Goodie Girl Gluten Free Mint Cookies. If using Girl Scout Thin Mint Cookies or Goodie Girl Gluten Free Mint Cookies you’ll need 16 cookies and if you’re using Oreo Mint Cookies you’ll need 13 cookies.
- Salt: Adds flavor. I like using sea salt or pink Himalayan salt.
- Pure Vanilla Extract: Gives flavor! I get my favorite pure vanilla extract from Costco.
- Mint Extract: You can also use peppermint extract.
- Heavy Cream: You can also use whole milk if you do not have heavy cream on hand.
- Unsweetened Cocoa Powder: Use natural cocoa powder in the cake, not dutch-process.
- Powdered Sugar: Also called confectioners sugar. PS- you do not need to sift it!
WHAT INGREDIENTS YOU NEED TO MAKE CHOCOLATE GANACHE
- Heavy Cream
- Chocolate Chips: I love using Guittard milk chocolate chips.
WHAT SUPPLIES YOU NEED
- 9×13 Inch Pan: Metal, glass or disposable pan is fine. Either will do. I love using Fat Daddio pans.
- Offset Icing Spatula: You can find one on Amazon or you can use the back of a spoon.
- Pipping Bags: I get mine from Amazon.
- Pipping Tips: 1M pipping tip. I get mine from Michaels.
- Food Processor
HOW TO MAKE A THIN MINT CHOCOLATE SHEET CAKE
Preheat the oven to 325°F. Generously grease a 9×13 inch cake pan.
In a food processor, blend up the mint cookies until a fine powder forms. Add in the melted butter and stir until combined.
Note: You’ll need 1 box (9 ounces or 32 cookies) of Girl Scout Thin Mint Cookies. If you can’t get your hands on Girl Scout Cookies you can substitute with Oreo Mint Cookies (10 ounces or 25 cookies) or Goodie Girl Gluten Free Mint Cookies (9 ounces so you’ll need at least 2 boxes).
Press the crust in the prepared baking pan and press firmly in an even layer with the bottom of a cup. Pre-baking is not required.
In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, vanilla, and mint extract until combined.
Mix in the unsweetened cocoa powder and cake box mix. Whisk until throughly combined.
Pour the batter into the prepared pan. Bake for 27 to 30 minutes or until a toothpick inserted in the center comes out clean. Baking times vary, so keep an eye on yours.
Remove from the oven and allow the cake to cool in the pan. Cool completely before decorating. As the cake is cooling, you can make the frosting and chocolate ganache to decorate the cake.
Tip: I like placing my cakes covered in the refrigerator or freezer while I make my frostings and/or toppings. I do this so that when I spread the frosting on the cold cake, the cake doesn’t pull away and I have no issues with crumbs in the frosting.
HOW TO MAKE THIN MINT CHOCOLATE BUTTERCREAM
In a food processor, blend up the Mint cookies until a fine powder forms. (Note: If using Girl Scout Thin Mint Cookies or Goodie Girl Gluten Free Mint Cookies you’ll need about 16 cookies and if you’re using Oreo Mint Cookies you’ll need about 13 cookies).
Using a hand-held mixer or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until light and fluffy, about 2 minutes. Add vanilla extract, mint extract, heavy cream, and salt with the mixer running on low. Slowly add the unsweetened cocoa powder, powdered sugar, and the mint cookie powder. Increase to high speed and beat for 3 full minutes. You can add more powdered sugar if frosting is too thin, more cream if the frosting is too thick, or a little more of salt if the frosting is too sweet.
Makes about 4 cups of frosting.
HOW TO MAKE CHOCOLATE GANACHE
Place chocolate chips and heavy cream in a microwave-safe bowl and microwave for 30 seconds.
Stir well, and then return to microwave and heat in 15-second increments, stirring well in between, until chocolate is completely melted and smooth. Set aside.
HOW TO DECORATE THE CAKE
Evenly spread the chocolate buttercream over the top of the cake using an icing spatula. I used about 2 cups of frosting. Place the cake in the freezer for 5 minutes. I like doing this so that when you pour the warm chocolate over the frosting it will set quicker.
Next, evenly spread the chocolate ganache over the frosting using an icing spatula. Place the cake in the freezer again for another 5 minutes.
Using a pipping bag filled with mint chocolate buttercream and a 1M pipping tip, pipe the design (see below) evenly all the way around the pan.
With the same 1M pipping tip pipe 3 even vertical lines. You might need to refill your bag with more frosting. Lastly, you can place the rest of your mint cookies on top of the cake (you can add 12 to 16). You can also chop up some mint cookies and sprinkle them evenly over the top of the cake.
If you’d like to take your decorating up a notch you can add gold edible glitter like it did.
Slice and serve. Cover leftovers tightly and store in the refrigerator for up to 5 days.
TIPS FOR MAKING THIS RECIPE
- Do not over-mix the batter as you risk over-developing the gluten leading to a tough, dry, and dense cake.
- All refrigerated items should be at room temperature so the batter mixes together easily and evenly.
- Make sure to allow the cake to cool before you add the buttercream.
- Make sure the butter is room temperature before you cream it, as cold butter will lead to lumpy buttercream.
- The longer you chill the cake, the better the buttercream will stick to the cake layers.
FREQUENTLY ASKED QUESTIONS
Can I make this cake in advance?
Yes! You can make the cake, the chocolate ganache, and buttercream frosting a few days ahead of time and keep them tightly wrapped in the fridge, then assemble them when you’re ready. You will need to pull out your buttercream from the refrigerator a few hours before you’d like to decorate to bring it back to a spreadable consistency. I would suggest once the buttercream has softened whip it up in your mixer before adding it to your pipping bags to decorate. You will also need to zap the chocolate ganache in the microwave for about 15 to 30 seconds. You can also make the entire cake in advance, wrap and place it in the fridge for up to 5 days.
Can I turn this recipe into a 2 layer cake?
Yes! Grease two 8 or 9 inch round cake pans (which ever size you have on hand), line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. Divide the batter evenly between the pans. Bake at 325°F for about 27 to 30 minutes—keep a close eye on the cakes and check for doneness with a toothpick.
Can I turn this recipe into a bundt cake?
Yes! Grease your bundt pan with. Bake at 325°F for about 25 to 35 minutes—keep a close eye on the cake and check for doneness with a toothpick.
Can I turn this recipe into cupcakes?
Yes! Using a cupcake pan fill cupcake liners 2/3 full. I love using this baking scoop for my regular sized cupcakes and this baking scoop and mini cupcake liners for my mini cupcakes. Bake at 350°F for about 14 to 19 minutes. Yields about 22 regular sized cupcakes. I would decorate by filling the cupcakes with chocolate ganache and topping the cupcakes with the mint cookie buttercream, and a mint cookie on top!
Can I make this with store bought frosting?
Yes! You can use any chocolate store bought frosting. I would suggest using 2 to 4 containers of the store bought frosting. Proceed to Step 6 on directions on how to add the crushed mint cookies and decorate the cake
I don’t like cake box mix, can I use a homemade sheet cake recipe?
Yes! You can use my chocolate sheet cake recipe.
Do I have to decorate it they way you did?
Of course not! If you think the way I designed this cake is too hard or not to your liking then be my guest to recreate your own design. You do you boo!
How do I store leftover frosting?
Buttercream frosting can be stored in the refrigerator for at least seven days. Just be sure that the container is tightly sealed and that you keep the frosting far from pungent foods like seafood since the smells can transfer. You can also freeze buttercream frosting for up to 3 months in an airtight container or freezer bag. The day before you’re ready to use it, let it thaw in the refrigerator overnight, then bring it to room temperature before re-whipping again. This is helpful if you’re making buttercream months in advance, or you have leftover frosting you’d like to use later on.
How do I store cake leftovers?
Cover and store leftover cake at room temperature for up to 3 days or refrigerate for up to 5 days. You can also freeze frosted cake or unfrosted cake can be frozen up to 2-3 months. Make sure to throughly wrap with plastic wrap and aluminum foil. Thaw overnight in the refrigerator and bring to room temperature before decorating/serving.
Make sure you post your photos on Instagram and tag me in them so I can see your creations from my blog #eazypeazylemonsqueezee
Thin Mint Cookie Sheet Cake
- March 5, 2024
- 12
- 4 hr
- Count the memories not the calories! Cals/Serving
- Print this
Ingredients
- Thin Mint Chocolate Cake:
- 32 (1 box) Thin Mint Cookies (or 25 (10 ounces) Oreo Mint Cookies or 9 ounces Goodie Girl Gluten Free Mint Cookies), pulsed to a powder in a food processor
- 4 tablespoons unsalted butter, melted
- 2/3 cup buttermilk, at room temperature
- 2/3 cup sour cream, at room temperature
- 3 eggs, at room temperature
- 1/3 cup oil (avocado oil, vegetable oil, canola oil or melted coconut oil)
- 1 Tablespoon pure vanilla extract
- 1/2 teaspoon mint extract
- 1/4 unsweetened natural cocoa powder
- 1 box chocolate cake mix
- Thin Mint Chocolate Buttercream:
- 1 cup (2 sticks) unsalted butter, at room temperature
- 1/4 teaspoon salt
- 1 Tablespoon pure vanilla extract
- 1/2 to 1 teaspoon mint extract
- 1 to 2 cups heavy cream
- 2/3 cup unsweetened natural cocoa powder
- 7 & 1/2 cups (2lbs) powdered sugar
- 16 Thin Mint Cookies (or 16 Goodie Girl Gluten Free Mint Cookies or 13 Oreo Mint Cookies), pulsed to a powder in a food processor
- Chocolate Ganache:1 cup chocolate chips
- 1/2 cup heavy cream
- Toppings:
- 12-16 Thin Mint Cookies (or Goodie Girl Gluten Free Mint Cookies or Oreo Mint Cookies)
- Edible gold glitter (optional)
- Supplies:
- 9x13 inch sheet pan
- Offset Icing Spatula
- Pipping bags
- Pipping tips 1M
- Food Processor
Directions
- Step 1
- PREP CAKE: Preheat the oven to 325°F. Generously grease a 9×13 inch cake pan.
- Step 2
- MAKE COOKIE CRUST: In a food processor, blend up the mint cookies until a fine powder forms. Add in the melted butter and stir until combined. (Note: You’ll need 1 box (9 ounces or 32 cookies) of Girl Scout Thin Mint Cookies. If you can’t get your hands on Girl Scout Cookies you can substitute with Oreo Mint Cookies (10 ounces or 25 cookies) or Goodie Girl Gluten Free Mint Cookies (9 ounces so you’ll need at least 2 boxes)). Press the crust in the prepared baking pan and press firmly in an even layer with the bottom of a cup. Pre-baking is not required.
- Step 3
- WET INGREDIENTS: In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, vanilla, and mint extract until combined.
- Step 4
- COMBINE: Mix in the unsweetened cocoa powder and cake box mix. Whisk until throughly combined.
- Step 5
- BAKE: Pour the batter into the prepared pan. Bake for 27 to 30 minutes or until a toothpick inserted in the center comes out clean. Baking times vary, so keep an eye on yours. Remove from the oven and allow the cake to cool in the pan. Cool completely before decorating. As the cake is cooling, you can make the frosting and chocolate ganache to decorate the cake. (Tip: I like placing my cakes covered in the refrigerator or freezer while I make my frostings and/or toppings. I do this so that when I spread the frosting on the cold cake, the cake doesn’t pull away and I have no issues with crumbs in the frosting).
- Step 6
- FOR THE THIN MINT CHOCOLATE FROSTING: In a food processor, blend up the Mint cookies until a fine powder forms. (Note: If using Girl Scout Thin Mint Cookies or Goodie Girl Gluten Free Mint Cookies you’ll need about 16 cookies and if you’re using Oreo Mint Cookies you’ll need about 13 cookies). Using a hand-held mixer or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until light and fluffy, about 2 minutes. Add vanilla extract, mint extract, heavy cream, and salt with the mixer running on low. Slowly add the unsweetened cocoa powder, powdered sugar, and the mint cookie powder. Increase to high speed and beat for 3 full minutes. You can add more powdered sugar if frosting is too thin, more cream if the frosting is too thick, or a little more of salt if the frosting is too sweet. Makes about 4 cups of frosting.
- Step 7
- FOR THE CHOCOLATE GANACHE: Place chocolate chips and heavy cream in a microwave-safe bowl and microwave for 30 seconds. Stir well, and then return to microwave and heat in 15-second increments, stirring well in between, until chocolate is completely melted and smooth. Set aside.
- Step 8
- DECORATE THE CAKE: Evenly spread the chocolate buttercream over the top of the cake using an icing spatula. I used about 2 cups of frosting. Place the cake in the freezer for 5 minutes. I like doing this so that when you pour the warm chocolate over the frosting it will set quicker. Next, evenly spread the chocolate ganache over the frosting using an icing spatula. Place the cake in the freezer again for another 5 minutes. Using a pipping bag filled with mint chocolate buttercream and a 1M pipping tip, pipe the design (see above) evenly all the way around the pan. With the same 1M pipping tip pipe 3 even vertical lines. You might need to refill your bag with more frosting. Lastly you can place the rest of your mint cookies on top of the cake (you can add 12 to 16). You can also chop up some mint cookies and sprinkle them evenly over the top of the cake. If you’d like to take your decorating up a notch you can add gold edible glitter like it did. Slice and serve.
- Step 9
- Cover leftovers tightly and store in the refrigerator for up to 5 days.
