An easy high altitude recipe for toasted hazelnut coffee cake, with a moist, fluffy texture and buttery hazelnut crumb topping. This cozy hazelnut crumb cake comes together quickly, so you don’t have to wait long to enjoy warm cake for breakfast or brunch.
You might also love these hazelnut shortbread cookies, no churn chocolate hazelnut ice cream, and hazelnut maple sugar cookie bars.
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Why You’ll Love This Recipe
Quick and Easy. The hazelnut cake batter and crumb topping comes together quickly, no mixer needed.
Great Leftover. Hazelnut coffee cake is really moist, buttery and nutty, and it’s still so delicious, even days after baking. The cake is best warmed up slightly in the microwave when eaten leftover.
Cake for Breakfast. I love any excuse to eat cake for breakfast, and coffee cake with crumb topping is the best kind of breakfast cake.
Cozy Flavors. With the nutty, toasted hazelnuts, the butter and sour cream, a hint of cardamom, cinnamon and espresso powder, and loads of crumbly topping, there’s so much to love about this hazelnut crumb cake.
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
- Flour. All purpose flour gives the cake and the crumb topping structure and strength.
- Sugar. To add moisture and sweetness, you’ll need light brown sugar for the cake, and a combination of brown sugar and granulated sugar in the crumble.
- Hazelnuts. Finely chopped hazelnuts in the cake and the topping adds nuttiness, moisture and the most delicious hazelnut flavor.
- Salt. Balances the sweetness and enhances the flavor of the hazelnuts.
- Baking Soda. Leavening agent, so the cake rises as it bakes.
- Butter + Oil. You’ll need butter for the topping, and a combination of melted butter and vegetable oil in the cake, to keep it moist, fluffy and rich tasting.
- Eggs. Gives the cake structure and moisture.
- Sour Cream. A hefty amount of sour cream keeps the cake moist, tender and flavorful.
- Spices. Cinnamon, cardamom, instant espresso powder and vanilla extract add warmth and coziness to complement the hazelnuts.
Instructions
Toast the Hazelnuts
- Preheat the oven to 300 F. Spread the hazelnuts for the cake and crumb topping out onto a baking sheet, and toast for 5-7 minutes, until hot and fragrant.
- Cool completely, and then finely chop the toasted hazelnuts. Set aside.
Make the cake batter.
- Preheat the oven to 350 F, and position a rack in the center of the oven. Lightly spray a 9-inch square baking pan with non stick baking spray.
- In a bowl, whisk together the flour, hazelnuts, salt, baking soda, cinnamon, cardamom and espresso powder, until evenly distributed.
- Separately, whisk together the brown sugar, eggs, sour cream, melted butter, oil and vanilla extract, until well combined.
- Add the wet ingredients to the dry, and use a spatula to fold the batter together just until moistened. Spread the batter into the prepared pan, and set aside while you make the topping.
Make the crumb topping.
- In a bowl, combine the flour, sugars, cinnamon, salt and hazelnuts. Add the melted butter, and stir until moistened and crumbly.
- Sprinkle the crumb topping evenly over the cake batter.
Bake the cake.
- Bake the cake for about 35-40 minutes, until the topping is golden brown, and a cake tester or sharp knife inserted in the center comes out clean.
- Set the cake on a cooling rack and let cool for about an hour. Serve warm, or at room temperature.
Recipe Variations
Add Chocolate Chips. I really went back and forth on whether or not to make this hazelnut coffee cake with chocolate chips or not. In the end, I left them out, but I still think a hazelnut chocolate chip coffee cake would be fantastic. Just add about 1/2 cup semi sweet chocolate chips to the cake batter. You could even sprinkle a few chips over the crumb topping, after taking the cake out of the oven.
Try Other Nuts. Instead of hazelnuts, simply substitute walnuts, pecans or almonds.
Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common baking questions, so that you can be successful in your own baking!
Frequently Asked Questions
Will any nuts work in this coffee cake recipe?
Yes, you can substitute other nuts for the hazelnuts. Almonds, walnuts and pecans would all work well.
Where do I find instant espresso powder?
I use Medaglia D’Oro Instant Espresso Coffee, which I buy at my local grocery store.
How should I store the leftover cake?
Keep leftover cake in an airtight container at room temperature for up to 3 days.
What’s the best way to reheat coffee cake?
Coffee cake is best enjoyed warm. Reheat individual pieces in the microwave for 30-45 seconds at 50% power.
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High Altitude Toasted Hazelnut Coffee 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
- 9 inch baking pan
Ingredients
Cake
- 1 ¾ cups all-purpose flour, fluffed, spooned and leveled
- ½ cup hazelnuts, finely chopped
- ½ tsp coarse Kosher salt (if using table salt, use half the amount)
- ½ tsp baking soda
- ¼ tsp ground cinnamon
- ¼ tsp ground cardamom
- 1 tsp instant espresso powder or instant coffee
- ½ cup light brown sugar, lightly packed
- 2 large eggs
- 1 cup full fat sour cream
- ¼ cup unsalted butter, melted
- ¼ cup vegetable oil
- 1 tsp vanilla extract
Crumb Topping
- 1 ½ cups all-purpose flour, fluffed, spooned and leveled
- â…“ cup granulated sugar
- â…“ cup light brown sugar, lightly packed
- ¼ tsp ground cinnamon
- ¼ tsp coarse Kosher salt (if using table salt, use half the amount)
- ¼ cup hazelnuts, roughly chopped
- ½ cup unsalted butter, melted
Instructions
Toast the Hazelnuts
- Preheat the oven to 300 F. Spread the hazelnuts for the cake and crumb topping out onto a baking sheet, and toast for 5-7 minutes, until hot and fragrant.
- Cool completely, and then finely chop the toasted hazelnuts. Set aside.
Cake Batter
- Preheat the oven to 350 F, and position a rack in the center of the oven. Lightly spray a 9-inch square baking pan with non stick baking spray.
- In a bowl, whisk together the flour, hazelnuts, salt, baking soda, cinnamon, cardamom and espresso powder, until evenly distributed.
- Separately, whisk together the brown sugar, eggs, sour cream, melted butter, oil and vanilla extract, until well combined.
- Add the wet ingredients to the dry, and use a spatula to fold the batter together just until moistened. Spread the batter into the prepared pan, and set aside while you make the topping.
Crumb Topping
- In a bowl, combine the flour, sugars, cinnamon, salt and hazelnuts. Add the melted butter, and stir until moistened and crumbly.
- Sprinkle the crumb topping evenly over the cake batter.
Bake
- Bake the cake for about 35-40 minutes, until the topping is golden brown, and a cake tester or sharp knife inserted in the center comes out clean.
- Set the cake on a cooling rack and let cool for about an hour. Serve warm, or at room temperature.
I just made this after about a month of planning to, and I’m glad I finally did. It is so yummy! The cardamom in it is perfect, and I love the crunchy bites from the nuts. Definitely a keeper.