High Altitude Mint Chocolate Chip Cake

This high altitude mint chocolate chip cake has three layers of soft, fluffy, dark chocolate cake with a hint of mint, frosted with mint chocolate chip buttercream. Swirls of frosting and squares of dark chocolate on top are the perfect decoration. I based this chocolate cake recipe on my best high altitude chocolate cake, which is always so moist, not to mention easy to make. Peppermint extract in both the cake and the buttercream transforms this cake into the most delicious mint chocolate dessert, while the chopped chocolate in the buttercream adds the best texture.

You might also love this no churn mint chocolate chip ice cream, chocolate chip cookie dough truffles, and chocolate white chocolate chip cookies.

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Why You’ll Love This Cake

Easy to Make. You’ll need a mixer to whip up the buttercream, but the cake batter is quick and easy to mix up with just a bowl and whisk.

Dark Chocolate. With dark, Dutch-processed cocoa powder and chocolate chips in the cake, chopped chocolate speckling the buttercream, and squares of chocolate decorating the cake, there’s enough chocolate in this cake to satisfy your chocolate cravings.

Fluffy, Soft, Creamy and Crunchy. There are so many good textures in this cake! Moist, fluffy chocolate cake. Creamy buttercream. Crunchy chocolate. They all work together perfectly.

High Altitude Tested. I develop all the recipes on my site for Denver’s altitude of 5,280 feet. If you’re at a lower or higher elevation, please see my FAQs for guidance on adjusting recipes for your altitude.

See the recipe card at the end of the post for the full ingredients list and instructions.

Ingredients

Cake

• All-Purpose Flour. Gives the cake strength and structure.
• Granulated Sugar. Adds sweetness and moisture.
• Cocoa Powder. Gives the cake its dark chocolate flavor and color. Be sure to use Dutch-processed cocoa powder, not natural cocoa powder.
• Baking Soda + Baking Powder. Leavens the cake to make it rise.
• Coarse Kosher Salt. Balances the sweetness and enhances the flavor of the chocolate.
• Eggs. Add structure.
• Whole Milk + Sour Cream. Fat, richness and acidity for a moist, tender cake crumb.
• Vegetable Oil. Moisture.
• Vanilla + Peppermint Extracts. Flavor.
• Chocolate Chips. Extra chocolate in a cake never hurts, right?

TIP: Be sure to use peppermint extract in the cake and buttercream, not mint extract. Peppermint extract has the best, true mint flavor for a mint chocolate chip cake, while mint extract tends to taste like spearmint gum or toothpaste.

Buttercream

• Unsalted Butter. Adds fat and flavor, and whips up light and fluffy when whipped with the powdered sugar. For a whiter buttercream (as pictured), substitute vegetable shortening for 50% of the butter.
• Powdered Sugar. Sweetens and thickens the buttercream.
• Meringue Powder. Gives frosting stability and improves the texture.
• Coarse Kosher Salt. Balances the sweetness.
• Vanilla + Peppermint Extracts. Flavor.
• Milk. Only use if needed to thin the buttercream to your desired consistency.
• Food Coloring. Since this is a mint chocolate chip cake, a popular choice is to tint the frosting green. I like the natural white color, but if you do choose to color your buttercream, be sure to use a gel food coloring.
• Chocolate. Use a good-quality chocolate, preferably dark, but you can use milk or semi sweet if that’s what you like. You’ll need to chop the chocolate fairly small, so that it will fleck the buttercream with pretty chocolate specks. I also sprinkled some in between the cake layers for extra crunch.

Instructions

Cake

• Preheat the oven to 350 F, and spray the bottoms of three 8-inch cake pans with non-stick spray.
• In a large bowl, sift together the flour, sugar, cocoa powder, baking soda, baking powder and salt.
• Separately, whisk together the eggs, milk, sour cream, oil, vanilla and peppermint extract. Add the wet ingredients to the dry, and whisk until combined, about 15 seconds. Use a spatula to fold in the chocolate chips.
• Divide the batter between the pans. Bake on the center oven rack for about 22-28 minutes, until the tops of the cakes spring back when lightly touched, or a toothpick inserted in the center comes out clean.
• Set the pans on a cooling rack, cover loosely with a clean kitchen towel, and cool completely before frosting.

Buttercream

• In the bowl of your stand mixer fitted with the whisk attachment, beat the butter on medium speed for 1 minute until smooth.
• With the mixer on low, gradually add the powdered sugar, meringue powder and salt, mixing to combine.
• Add the vanilla and peppermint extract, and increase the speed to medium (#4-6 on a Kitchen Aid mixer); whip for 4-5 minutes until very light and fluffy, scraping the bowl down occasionally, and only adding the milk if needed for desired consistency.Turn the speed down to “stir” and mix for 2 minutes to eliminate big air bubbles.

Assembly

• Remove the cooled cakes from the pans. Place one cake layer on a cake board, and frost with a layer of buttercream. Sprinkle with a tablespoon of the chopped chocolate. Top with the second cake layer, more buttercream and more chopped chocolate. Top with the third cake layer, then frost all over with a thin “crumb coat” of buttercream.
• Refrigerate for 30 minutes to set the crumb coat. Fold the remaining chopped chocolate into the remaining buttercream, and frost the cake all over with a final coat of buttercream.
• If desired, fit a piping bag with tip 6B, fill with the remaining buttercream, and pipe swirls on top of the cake. Top each swirl with a square of chocolate.

Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common questions with cake making, so that you can be successful in your own baking! I also suggest reading these comprehensive posts on making Perfect American Buttercream, How to Stack, Fill, Crumb Coat and Frost Layer Cakes and How to Use Piping Bags.

Frequently Asked Questions

Can I still make this recipe if I don’t live at high altitude?

You sure can! If you’re at low altitude or sea level, you’ll probably need to make a few minor adjustments like decreasing the flour by a few tablespoons and increasing the leavening a little. You can refer to this guide for specific adjustments.

Should I use peppermint extract or mint extract?

Be sure to use peppermint extract in the cake and buttercream, not mint extract. Peppermint extract has the best, true mint flavor for baking, while mint extract tends to taste like spearmint gum or toothpaste.

What piping tip did you use for the buttercream swirls on top?

Tip 6B.

What kind of chocolate is on top of the cake?

I decorated the top of the cake with squares of Endangered Species Mint Dark Chocolate.

Can I use chocolate chips in the buttercream instead of chopped chocolate?

If you want, you can use mini chocolate chips in the buttercream. But if you chop a bar of chocolate, you’ll get a variety of little chunks and shards which adds beautiful flecks of chocolate all throughout the frosting.

What size pans should I use if I cut this recipe in half?

You can make half the cake recipe and bake it in three 6-inch cake pans. This post’s photographed cake is a half-size 6-inch cake. Note that you should make 3/4 of the frosting recipe for a 6-inch cake, if you want enough frosting to pipe the swirls on top.

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