This decadent high altitude chocolate hazelnut cake has three layers of moist chocolate cake, filled and frosted with salted chocolate Nutella buttercream and toasted hazelnuts. Top with more hazelnuts, or even Ferrero Rocher chocolate hazelnut truffles for a simple but delicious decoration. If you love chocolate hazelnut truffles, this is the cake for you!
You might also love these chocolate hazelnut linzer cookies, chocolate hazelnut cupcakes, and toasted hazelnut Christmas cookies.
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Why You’ll Love This Recipe
The Best Flavors and Textures. There’s no denying that a chocolate hazelnut truffle is one of the best treats during the holidays. This chocolate hazelnut cake combines all the flavors and textures of the truffles into a moist, chocolatey, simply delicious cake.
Salty and Sweet. The best desserts have a hint of salt in them, and the coarse Kosher salt in the cake and buttercream really brings out the nuttiness of the hazelnuts.
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
Chocolate Cake
- Flour. Plain, all-purpose flour gives this cake structure and strength.
- Sugar. Granulated sugar adds sweetness and moisture.
- Cocoa Powder. Use unsweetened, Dutch-processed cocoa powder for a deep, rich chocolate flavor and dark color.
- Baking Powder + Baking Soda. Leavens the cake so it rises as it bakes.
- Salt. Coarse Kosher salt balances the sweetness in the cake and enhances the flavor of the chocolate and hazelnuts.
- Eggs. Eggs give cakes structure, as well as fat and richness.
- Milk + Sour Cream. Adds moisture, flavor and acidity. Be sure to use whole milk and full fat sour cream for the best flavor.
- Vegetable Oil. Oil, rather than butter, makes a very moist cake with a light texture.
- Vanilla Extract. Flavor.
- Espresso Powder. Enhances the flavor of the chocolate.
Buttercream
- Hazelnuts. The hazelnuts add the best crunch and texture in the buttercream. Be sure to toast them first, to deepen their flavor.
- Butter. I use unsalted butter in my buttercream, and then add salt, but if you use salted butter, just reduce or omit the extra salt.
- Powdered Sugar. Sweetens and thickens the buttercream.
- Cocoa Powder. Use unsweetened, Dutch-processed cocoa powder for a deep, rich chocolate flavor and dark color.
- Meringue Powder. Adds stability and improves the texture.
- Salt. Balances the sweetness and enhances the flavor of the hazelnuts.
- Vanilla Extract. Flavor.
- Milk. Only add as needed, to thin the buttercream if it’s too stiff.
- Chocolate Hazelnut Spread. Gives the buttercream its chocolate hazelnut flavor.
Instructions
Cake
- Preheat the oven to 350 F, and position a rack in the center of the oven. Spray the bottoms of three 8-inch round cake pans with non-stick spray. If making half the recipe, use three 6-inch round cake pans.
- In a bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda and salt, then whisk until completely combined.
- In another large bowl, whisk together the eggs, milk, sour cream, oil, vanilla and espresso powder until smooth. Add the dry ingredients to the wet, and whisk for about 15-20 seconds until well combined and mostly free of lumps.
- Divide the batter between the pans. Tap the pans lightly on the counter a few times to pop any large air bubbles. Bake the cakes on the center rack for about 25-30 minutes, until a toothpick or cake tester comes out clean or with moist crumbs clinging to it, and the tops spring back when gently touched.
- Set the pans on a cooling rack, cover loosely with a clean kitchen towel and cool completely before frosting.
Buttercream
- First, toast the hazelnuts. Preheat the oven to 300 F. Spread the hazelnuts out onto a baking sheet, and toast for 5-7 minutes, until hot and fragrant. Cool completely, and then finely chop half the nuts, keeping the rest whole for decorating. Set aside.
- In the bowl of your stand mixer fitted with the paddle attachment, beat the butter for one minute until smooth.
- With the mixer on low, add the powdered sugar, cocoa powder, meringue powder and salt, mixing to combine.
- Add the vanilla; whip on medium speed for 4-5 minutes, scraping the bowl occasionally, until very light and fluffy. Add the milk as needed, for desired spreading consistency.
- Add 1/2 cup of the Nutella, mixing on low to combine.
Assembly
- Remove the cooled cakes from the pans. Set one cake layer on a cake plate.
- Spread 1/4 cup of Nutella over the cake, then sprinkle with half the chopped nuts, pressing them into the Nutella. Spread a layer of buttercream over the hazelnuts. The nuts can make it difficult to add the frosting layer, so if you like, simply fold the chopped hazelnuts into the buttercream for easier assembly. Otherwise, you may need to use a piping bag to pipe a layer of buttercream on top of the nuts.
- Repeat the above step with a second layer of cake, Nutella, hazelnuts and buttercream, then place the third cake layer on top.
- Frost the cake all over with a thin crumb coat of buttercream. Chill in the refrigerator for 20-30 minutes, then finish frosting the cake with a final layer of buttercream, and decorate with more hazelnuts.
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
If you use larger pans, your cake layers will be thinner, so the finished cake won’t be as tall. I’d recommend increasing the recipe by 1 1/2x for 9 inch pans.
The cake should be kept in an airtight container or cake carrier at room temperature for up to three days.
To make the cake in advance, bake and cool the cake, wrap each layer individually in plastic wrap, and freeze for up to 3-6 months. Let thaw overnight at room temperature before frosting. You can make the buttercream in advance as well, keeping it refrigerated in an airtight container for 3 days, or frozen for up to 3-6 months. You may need to re-whip the buttercream if it’s been frozen for a while.
You can find my chocolate hazelnut cupcake recipe here.
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High Altitude Chocolate Hazelnut Cake
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet. See FAQs for adjusting to higher or lower elevations.
Equipment
- Stand Mixer with Paddle Attachment
- 8-inch cake pans (x3)
Ingredients
Chocolate Cake
- 2 cups all-purpose flour, fluffed, spooned and leveled
- 1 ¾ cups granulated sugar
- ¾ cup unsweetened Dutch-processed cocoa powder
- ½ tsp baking powder
- 1 ¼ tsp baking soda
- 1 tsp coarse Kosher salt (if using table salt, use half the amount)
- 4 large eggs
- 1 cup whole milk, room temperature
- 1 cup vegetable oil
- 1 cup full-fat sour cream, room temperature
- 2 tsp vanilla extract
- 1 tbsp instant espresso powder
Buttercream & Filling
- ¾ cup shelled hazelnuts
- 2 cups unsalted butter, softened to room temperature
- 3 cups powdered sugar
- 1 cup unsweetened Dutch processed cocoa powder
- 1 tbsp meringue powder, optional
- 1/4-1/2 tsp coarse Kosher salt (if using table salt, use half the amount)
- 1 cup Nutella or chocolate hazelnut spread, divided
- 2 tsp vanilla extract
- 2-4 tbsp milk, if needed
Instructions
Cake
- Preheat the oven to 350 F, and position a rack in the center of the oven. Spray the bottoms of three 8-inch round cake pans with non-stick spray. If making half the recipe, use three 6-inch round cake pans.
- In a bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda and salt, then whisk until completely combined.
- In another large bowl, whisk together the eggs, milk, sour cream, oil, vanilla and espresso powder until smooth. Add the dry ingredients to the wet, and whisk for about 15-20 seconds until well combined and mostly free of lumps.
- Divide the batter between the pans. Tap the pans lightly on the counter a few times to pop any large air bubbles. Bake the cakes on the center rack for about 25-30 minutes, until a toothpick or cake tester comes out clean or with moist crumbs clinging to it, and the tops spring back when gently touched.
- Set the pans on a cooling rack, cover loosely with a clean kitchen towel and cool completely before frosting.
Buttercream
- First, toast the hazelnuts. Preheat the oven to 300 F. Spread the hazelnuts out onto a baking sheet, and toast for 5-7 minutes, until hot and fragrant. Cool completely, and then finely chop half the nuts, keeping the rest whole for decorating. Set aside.
- In the bowl of your stand mixer fitted with the paddle attachment, beat the butter for one minute until smooth.
- With the mixer on low, add the powdered sugar, cocoa powder, meringue powder and salt, mixing to combine.
- Add the vanilla; whip on medium speed for 4-5 minutes, scraping the bowl occasionally, until very light and fluffy. Add the milk as needed, for desired spreading consistency.
- Add 1/2 cup of the Nutella, mixing on low to combine.
Assembly
- Remove the cooled cakes from the pans. Set one cake layer on a cake plate.
- Spread 1/4 cup of Nutella over the cake, then sprinkle with half the chopped nuts, pressing them into the Nutella. Spread a layer of buttercream over the hazelnuts.The nuts can make it difficult to add the frosting layer, so if you like, simply fold the chopped hazelnuts into the buttercream for easier assembly. Otherwise, you may need to use a piping bag to pipe a layer of buttercream on top of the nuts.
- Repeat the above step with a second layer of cake, Nutella, hazelnuts and buttercream, then place the third cake layer on top.
- Frost the cake all over with a thin crumb coat of buttercream. Chill in the refrigerator for 20-30 minutes, then finish frosting the cake with a final layer of buttercream, and decorate with more hazelnuts.
Notes
Can I replace the sugar with maple syrup?
Sarah, different sugars have different chemical properties, and replacing the sugar with maple syrup would probably change the cake’s texture. Since I haven’t tested it, I couldn’t vouch for the results.
Hi,
Your recipes look great but I’m in NY and definitely not at a high altitude. Can you please give me info on any changes I might have make to have this cake, or any other recipe on your site, work out well? I’m looking for general info.
Thank you,
Amy
Amy, please see my FAQs for some helpful information and links: https://curlygirlkitchen.com/baking-faqs/
Obsessed with this recipe. I made it for my dads birthday, and everyone loved it. Will definitely be making again!
Creamy, crunchy, deliciously special cake, Heather. We really enjoyed making it together. My one daughter who is just not a fan of chocolate cakes, but loves chocolate, decided that this recipe is the only chocolate cake she wants to eat–ever again! Congrats and much thanks for another special cake recipe–so timely for the holidays.