Chocolate Sponge Cake Recipe

Prep

Preheat the oven to 350°F (175°C). Butter an 8-inch round springform or cake pan and dust with cocoa powder; tap out excess.

Dry ingredients

In a medium bowl sift together the all-purpose flour, unsweetened cocoa powder, baking powder and sea salt. Whisk to combine and set aside.

Whisk eggs and sugar

In a large mixing bowl or the bowl of a stand mixer fitted with the whisk attachment, combine the 4 large eggs and 1 cup granulated sugar. Whisk on high speed for 6–8 minutes until the mixture is thick, pale, and tripled in volume (ribbon stage). If using a hand whisk, whisk vigorously for 10–12 minutes.

Incorporate oil and milk

With the mixer on low, drizzle in the 1/4 cup vegetable oil until incorporated, then add the 1/4 cup whole milk and 1 tsp vanilla extract and mix just to combine.

Fold in dry ingredients

Sift one-third of the dry ingredients over the egg mixture and fold gently using a silicone spatula to preserve air. Repeat with the remaining dry ingredients in two more additions until just combined—do not overmix. The batter should be light and airy.

Bake

Pour the batter into the prepared pan, smooth the top, and bake 22–26 minutes or until the top springs back lightly and a toothpick inserted into the center comes out with a few moist crumbs. Avoid overbaking to keep the sponge tender.

Cool

Remove cake from the oven, let rest in pan for 10 minutes, then run a knife around the edge and invert onto a wire rack to cool completely, top-side up. If using a springform, release after 10 minutes and cool on rack.

Combine the raspberries and 1/2 cup granulated sugar in a small saucepan over medium heat. Stir to combine and bring to a gentle simmer.

Use a wooden spoon to break down the berries as they soften. Simmer gently, stirring occasionally, until the mixture reduces and thickens about 10–12 minutes. If you want a smoother jam, press through a fine-mesh sieve to remove seeds; otherwise leave as is for texture.

Stir in 1 tbsp lemon juice and, if using, 1 tsp pectin. Simmer 1–2 more minutes, then remove from heat and let cool to room temperature. The marmalade will thicken further as it cools.

Make caramel

In a heavy-bottomed saucepan over medium heat, combine 3/4 cup granulated sugar and 2 tbsp water. Swirl the pan gently (do not stir) until the sugar dissolves and starts to caramelize. Continue cooking, watching color closely, until it reaches a deep amber color (about 6–9 minutes).

Add cream and butter

Immediately and carefully add 3/4 cup warm heavy cream (the mixture will steam and bubble vigorously). Stir with a heatproof spatula until smooth. Add 3 tbsp unsalted butter and stir until incorporated. Remove from heat.

Combine with chocolate

Place the 6 oz chopped bittersweet chocolate in a heatproof bowl. Pour the hot caramel-cream mixture over the chocolate and let sit 1–2 minutes to melt. Stir gently until the chocolate is fully melted and the ganache is glossy. Stir in 1/4 tsp flaky sea salt. If ganache is too thin for spreading, cool until thickened to desired consistency.

Level the cooled sponge if necessary by trimming the domed top with a serrated knife to create a flat surface.

If serving as a single-layer cake: place the cooled cake on a serving plate. Spread an even layer (about 1/2 cup) of the raspberry marmalade over the top, leaving a small border around the edge if desired.

Pour the warm (but not hot) chocolate caramel ganache over the center of the cake and gently spread toward the edges with an offset spatula so it slightly drips over the sides. Use the back of a spoon to coax a gentle drip if desired.

Garnish: Arrange fresh raspberries on top and sprinkle a light pinch of powdered sugar if desired. Allow ganache to set for 20–30 minutes at room temperature (or chill 10–15 minutes in the refrigerator for a firmer set).

Slice and serve: use a sharp knife dipped in hot water and wiped dry between cuts for clean slices. Store any leftovers covered in the refrigerator for up to 3 days; bring to room temperature before serving.