Crumbly Hazelnut Coffee Cake Recipe

Coffee cake is a popular and versatile baked treat, perfect for sharing with guests. Despite the name, most coffee cake recipes don't actually contain any coffee, rather this simple lightly sweet cake is meant to be an accompaniment to coffee or tea. Coffee cake usually has a tender crumb, often has a streusel topping, and is a staple for casual get-togethers, brunches, morning meetings, or even as a comforting snack or dessert. Its simplicity makes it suitable for a wide range of occasions, from a family breakfast to an elegant afternoon tea.

The simplicity of a traditional coffee cake recipe also makes it perfect for customization: There are many ways to adapt this classic recipe, and adding toasty, crunchy hazelnuts is a great place to start. The nuttiness of the hazelnuts complements the sweet, soft base of the cake and provides a delightful contrast in textures. Whether it's for a cozy family gathering, a festive holiday brunch, or simply a moment of solitary enjoyment with a good book and a hot beverage, a slice of hazelnut coffee cake can elevate the experience.

This recipe is not unlike your typical coffee cake, but with a twist. The base is made of flour, sugar, vanilla, eggs, butter, salt, baking powder, baking soda, and milk. Greek yogurt adds moisture and protein, but can be substituted with sour cream for extra tang. There's a bit of almond meal to add nuttiness to the base cake to complement the hazelnuts, which appear in the topping. The topping also has some butter, along with brown sugar and cinnamon. The cake is swirled with a bit of chocolate hazelnut spread, commonly sold as Nutella in stores.

Preheat the oven to 325 F.

Prepare a 9 x 13-inch baking pan by spraying it with nonstick spray and lining it with parchment paper.

In a medium bowl, whisk together 2 ¾ cup flour, baking powder, baking soda, and salt.

In the bowl of a stand mixer fitted with the paddle attachment, beat ¾ cup butter and sugar until fluffy.

Add the eggs one at a time, scraping the bowl between additions.

Alternate additions of yogurt, almond flour, flour mixture, and milk until fully combined.

Fold in the vanilla.

Mix in the Nutella, leaving streaks of it in the batter.

Transfer the batter to the prepared pan.

Spread the batter in an even layer.

In a medium bowl, combine 4 tablespoons of butter, brown sugar, cinnamon, and ½ cup flour.

Mash with your fingers until clumpy.

Mix in the hazelnuts.

Scatter the hazelnut crumb mixture over the top of the batter.

Transfer the cake to the oven and bake until a toothpick inserted into the center comes out clean, about 25 minutes.

Remove the cake from the oven and let cool.

Slice before serving.

One of the keys to ensuring that this cake remains moist is in the preparation of the batter. The recipe includes ingredients like Greek yogurt, milk, and unsalted butter, all of which contribute to the moisture content of the cake. It's crucial to use room temperature ingredients, as this helps them to blend more easily so you can avoid overmixing. If you overmix the batter you'll develop the gluten too much and end up with a dense, dry cake. When adding the eggs, yogurt, almond flour, flour mixture, and milk, do so gradually and mix just until each addition is incorporated. This helps maintain the tender crumb of the cake. 

Additionally, the baking time and temperature are essential factors. Bake the cake at 325 F as directed, and start checking for doneness around the 20-minute mark. A toothpick inserted into the center of the cake should come out clean. Overbaking is a common reason for dryness in cakes, so monitor the process carefully towards the end of the baking time. Finally, let the cake cool in the pan, which allows it to reabsorb some of the steam it released while baking, further retaining the moisture.

You can certainly use other nuts in this recipe, both in the cake batter and the hazelnut crumb topping. The original recipe calls for hazelnuts, which provide a distinct and elegant flavor and texture, but you can experiment with several other kinds of nuts that would also work well. Walnuts or pecans are great substitutes for hazelnuts in the crumb topping. They both have a rich, buttery flavor and add a lovely crunch. You can chop them coarsely and use them in the same quantity as the hazelnuts. Since the recipe already includes almond flour, using sliced or chopped almonds in the topping will enhance the almond flavor throughout the cake.

Pistachios would be a unique and colorful addition for a slightly different flavor profile. They pair well with the Nutella and vanilla flavors in the cake. Macadamia nuts offer a creamy texture and a subtle taste, which would provide a nice contrast to the sweetness of the cake. When substituting nuts, it's important to consider their distinct flavors and how they might affect the overall taste of the cake. Opt for dry roasted nuts, but don't toast them: The nuts undergo toasting while the cake bakes and you want to avoid burning.