Ingredients
Chocolate Cake
- 240 grams (2 cups) all purpose flour
- 1 teaspoon baking soda
- 1 teaspoon kosher salt
- 170 grams (¾ cup; 6 ounces) unsalted butter, melted
- 45 mL (3 Tablespoons) vegetable oil, neutral flavor
- 300 grams (1½ cups) granulated sugar
- 30 grams (¼ cup + 2 Tablespoons) Dutch process cocoa powder
- 250 mL (1 cup) strong brewed hot coffee
- 2 large eggs, room temperature
- 120 grams (½ cup) full-fat sour cream
- 1½ teaspoons vanilla extract
- 66 grams (½ cup) walnuts, toasted and chopped
Whipped Chocolate Ganache Topping
- 188 mL (¾ cup; 6 ounces) heavy cream
- 170 grams (6 ounces) dark chocolate (60% cacao), finely chopped
- 33 grams (¼ cup) walnuts, toasted and chopped, to sprinkle on top
Instructions
- Preheat and prepare pan: Preheat oven to 350°F (177°C). Line the bottom and sides of an 8-inch (20 cm) square cake pan with parchment paper to prevent sticking.
- Toast walnuts: Spread all walnuts (for cake and topping) on a rimmed baking sheet and toast in the oven for 5-8 minutes, watching carefully to avoid burning. Remove and let cool, then chop into small pieces.
- Mix dry ingredients: In a medium bowl, sift together the all-purpose flour, baking soda, and kosher salt. Set aside.
- Combine wet ingredients: In a large mixing bowl, whisk melted butter, vegetable oil, granulated sugar, and Dutch process cocoa powder until thoroughly mixed. Add the hot coffee and whisk to combine smoothly.
- Add eggs: Add eggs one at a time, whisking well after each to fully incorporate.
- Incorporate dry ingredients and sour cream: Whisk in the dry ingredient mixture until no flour pockets remain, scraping the bowl as needed. Add sour cream and vanilla extract, whisking until the batter is smooth and homogeneous.
- Fold in walnuts and pour batter: Gently fold in half the toasted chopped walnuts (½ cup). Pour the batter into the prepared pan and firmly rap the pan on the countertop to release air bubbles.
- Bake the cake: Bake on the center rack for 45-50 minutes, or until a toothpick inserted in the center comes out clean, the cake springs back lightly when touched, and it begins pulling away from the pan edges.
- Cool the cake: Let the cake cool in the pan for 10-15 minutes, then invert onto a cooling rack and remove the parchment. Cool completely before frosting.
- Make whipped chocolate ganache: Heat the heavy cream in a microwave-safe container or small saucepan just until almost simmering. Remove from heat and add chopped dark chocolate. Let sit for 2-3 minutes, then whisk until completely smooth and no lumps remain.
- Cool ganache to room temperature: Allow ganache to cool to room temperature. To speed this up, place the bowl in the refrigerator for 2-3 intervals of 10 minutes, whisking every 10 minutes. Do not chill it cold.
- Whip the ganache: Transfer the cooled ganache to a stand mixer bowl fitted with a whisk attachment. Whisk on high for 1 minute, scraping down the bowl several times to ensure even whipping. The ganache should become lighter in color, fluffy, and hold firm peaks.
- Frost and decorate the cake: Using a small offset spatula, spread the whipped ganache evenly over the top of the cooled cake, leaving the sides bare. Sprinkle the remaining ¼ cup toasted walnuts evenly over the top as garnish.
Notes
- Toasting walnuts brings out their flavor but watch carefully to avoid over-toasting which causes bitterness.
- Using strong brewed coffee enhances the chocolate flavor but can be substituted with hot water if preferred.
- Ensure eggs are at room temperature for better batter emulsion.
- Do not overwhip the ganache as it might become grainy; stop once it holds firm peaks.
- Leaving the sides of the cake unfrosted gives a rustic, elegant look and focuses attention on the top garnishing.
- This cake keeps well stored in an airtight container in the refrigerator for up to 3 days.
- Prep Time: 20 minutes
- Cook Time: 50 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
