Hazelnut Espresso Cake with Chocolate Glaze

Ingredient Deep Dive

Raw Hazelnuts: 150g (approx. 1 ½ cups), skinless or skin-on
All-Purpose Flour: 140g (1 cup)
Unsweetened Dutch-Process Cocoa Powder: 30g (⅓ cup)
Baking Powder: 1 ½ teaspoons
Baking Soda: ½ teaspoon
Fine Sea Salt: ½ teaspoon
Instant Espresso Powder: 2 tablespoons (dissolved in 2 tablespoons hot water)
Unsalted Butter: 170g (¾ cup), softened to room temperature
Granulated Sugar: 200g (1 cup)
Large Eggs: 3, at room temperature
Pure Vanilla Extract: 1 ½ teaspoons
Whole Milk or Buttermilk: 120ml (½ cup), at room temperature

Preheat your oven to 175°C (350°F).
Spread the raw hazelnuts evenly over a rimmed baking sheet.
Roast in the oven for 8 to 10 minutes until golden and fragrant.
If using skin-on hazelnuts, immediately transfer them onto a clean kitchen towel, fold the towel over, and rub vigorously to shed the loose, bitter skins. Discard the skins.
Allow nuts to cool completely. Transfer 150g of the nuts to a food processor along with 2 tablespoons of the all-purpose flour (to prevent clumping) and pulse until you achieve a fine, sand-like meal. Avoid over-processing into nut butter.

Lightly grease an 8-inch or 9-inch springform or round cake pan with butter and line the bottom with a circle of parchment paper. Dust the sides lightly with cocoa powder.
In a medium mixing bowl, whisk together the ground hazelnut flour, remaining all-purpose flour, Dutch-process cocoa powder, baking powder, baking soda, and fine sea salt.

In a large bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter and granulated sugar on medium-high speed for 3 to 4 minutes until light and fluffy.
Add the room-temperature eggs one at a time, beating thoroughly after each addition. Scrape down the sides of the bowl.
Stir in the pure vanilla extract and the prepared espresso liquid.
Reduce the mixer speed to low. Add one-third of the dry ingredients, followed by half of the milk. Alternate with the remaining dry ingredients and milk, mixing just until combined. Avoid overmixing to keep the crumb delicate and soft.

Pour the batter into the prepared pan and smooth the top with an offset spatula.
Bake at 175°C (350°F) for 32 to 36 minutes, or until a wooden skewer inserted into the center emerges clean or with a few moist crumbs attached.
Remove the cake from the oven and place it on a wire cooling rack. Let it cool in the pan for 15 minutes, then run a thin knife around the edges and release the cake onto the wire rack to cool completely.

Place the chopped dark chocolate and ½ teaspoon of instant espresso powder in a heatproof bowl.
In a small saucepan over medium-low heat, bring the heavy whipping cream, butter, and corn syrup just to a gentle simmer (do not let it boil vigorously).
Pour the hot cream mixture over the chopped chocolate. Let it sit undisturbed for 2 to 3 minutes to melt the chocolate evenly.
Gently whisk from the center outward in small circles until the ganache is uniform, smooth, and glossy.
Allow the glaze to sit at room temperature for 8 to 10 minutes to thicken slightly into a pourable consistency.

Place the completely cooled cake on a serving plate or keep it over the wire rack set over a baking sheet to catch excess drips.
Pour the chocolate glaze directly into the center of the cake, gently nudging it outward with an offset spatula so it cascades naturally down the sides.
Sprinkle the top border with roughly chopped toasted hazelnuts and a delicate pinch of flaky sea salt.
Allow the glaze to set for 20 to 30 minutes at room temperature before slicing.

Element	Level / Intensity	Profile Characteristics
Sweetness	Mild-Moderate	Controlled to let the coffee and hazelnut aromatics lead.
Espresso Intensity	Medium-Bold	Deep roasted notes without overwhelming bitterness.
Nutty Richness	High	Ground toasted hazelnut provides earthy warmth and body.
Crumb Density	Medium	Tender, rich, and moist due to natural nut oils.
Glaze Texture	Silk / Mirror Gloss	Smooth melt-in-mouth finish with rich dark chocolate notes.

Nut Milling Technique: Always pulse hazelnuts in short bursts with a spoonful of flour. Hazelnuts release oils quickly; pulsing keeps the texture crumb-like rather than pasty.
Espresso Choice: High-grade espresso powder or finely pulverized instant dark roast creates the most aromatic flavor bloom. Avoid brewed drip coffee as it introduces excess moisture without enough flavor concentration.
Temperature Timing: Ensure your eggs, milk, and butter are at identical room temperatures (~20°C / 68°F) to prevent the batter emulsion from splitting.

Room Temperature: Store under a cake dome or airtight container for up to 3 days.
Refrigeration: Store refrigerated for up to 5 days. Bring slices to room temperature 30 minutes prior to serving for optimal texture and flavor.
Freezing: The unglazed cake can be wrapped tightly in plastic wrap and aluminum foil, then frozen for up to 2 months. Thaw overnight in the refrigerator and bring to room temperature before glazing.

Serving Size: 1 slice (based on 10 servings)