Ingredients

1 ¼ cups (213 grams) semisweet chocolate chips

1 stick (113 grams) unsalted butter

3/4 cup (150 grams) granulated sugar

1 teaspoon instant espresso powder (optional)

1/4 teaspoon fine sea salt

1 teaspoon vanilla extract

3 large eggs plus 1 egg yolk

1/2 cup (43 grams) Dutch-process cocoa powder

½ cup (120 grams) heavy cream, chilled

Powdered sugar (for dusting)

Freshly whipped cream, vanilla ice cream, or 1:1 ganache (for serving)

Fresh strawberries or raspberries (for garnish)

Instructions

Step 1: Preheat the oven to 350°F. Lightly grease an 8-inch round, 3-inch deep cake pan with nonstick cooking spray. Place a parchment paper round on the bottom of the pan and spray again to prevent sticking.

Step 2: In a large microwave-safe bowl, heat the semisweet chocolate chips and butter in 30-second increments, stirring after each, until just melted. Stir until smooth.

Step 3: Whisk in the sugar, instant espresso powder (if using), salt, and vanilla extract. Allow the mixture to cool slightly.

Step 4: Add the eggs and extra yolk all at once, whisking vigorously until the mixture is smooth and shiny. Then whisk in the cocoa powder until just combined. The batter will be thick.

Step 5: In a separate bowl, use an electric mixer or immersion blender to whip the chilled heavy cream to medium peaks. Gently fold the whipped cream into the chocolate batter using a rubber spatula until fully incorporated.

Step 6: Pour the batter into the prepared pan and smooth the top evenly.

Step 7: Bake for 25 to 30 minutes, until the cake has puffed up, the edges are set, but the center still has a slight wobble. The center should reach at least 200°F on an instant-read thermometer.

Step 8: Remove the cake from the oven and cool in the pan on a wire rack for 10 minutes. The cake will deflate slightly as it cools. Carefully loosen the edges with a thin knife to aid unmolding later, then let the cake cool completely in the pan.

Step 9: Cover and refrigerate the cake for at least 6 hours or overnight. The cake can be refrigerated, covered, for up to 3 days.

Step 10: When ready to serve, transfer the cake to a plate. Use a sharp knife dipped in hot water and wiped clean between cuts to slice the cake neatly. Dust the top with powdered sugar and garnish with whipped cream or ice cream and fresh berries. Serve chilled.

Tips & Variations

For an extra mocha flavor, be sure to include the espresso powder—it enhances the chocolate without adding coffee taste.

If you don’t have Dutch-process cocoa, natural cocoa powder can be used, but the flavor will be slightly different.

Substitute the whipped cream topping with your favorite ganache or serve with a scoop of rich vanilla ice cream for a delightful contrast.

FAQs

Can I make this cake gluten-free?

Yes, this cake is naturally gluten-free since it contains no flour. Just ensure all ingredients, like cocoa powder and chocolate chips, are certified gluten-free if needed.

Why does the cake need to be refrigerated overnight?

Chilling allows the cake to set fully, improving its texture and making it easier to slice cleanly. It also intensifies the rich chocolate flavor and gives the cake its characteristic fudgy consistency.