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Dark Chocolate Mousse Cake Recipe

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4.3 from 14 reviews

This decadent Dark Chocolate Mousse Cake features moist, rich chocolate layers made with cocoa powder and espresso powder, layered with a luscious chocolate mousse, and finished with a silky chocolate ganache. Perfectly balanced with tangy sour cream and buttermilk, this cake is ideal for chocolate lovers seeking a luxurious dessert for special occasions.

Ingredients

Cake Ingredients

  • 1 and 3/4 cups (219g) all-purpose flour (spooned & leveled)
  • 1 and 3/4 cups (350g) granulated sugar
  • 3/4 cup (64g) unsweetened natural cocoa powder
  • 2 teaspoons espresso powder (optional)
  • 2 teaspoons baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 3/4 cup (180g) full-fat sour cream, at room temperature
  • 1/2 cup (113g/120ml) vegetable oil
  • 2 large eggs, at room temperature
  • 1/2 cup (120g/ml) buttermilk, at room temperature
  • 2 teaspoons pure vanilla extract
  • 1/2 cup (120g/ml) hot water or black coffee
  • 1 cup (170g) semi-sweet mini chocolate chips tossed in 1 Tbsp flour (optional)

Chocolate Mousse Ingredients

  • 1/2 cup (120g/ml) hot water
  • 1/4 cup (21g) unsweetened natural or Dutch-process cocoa powder
  • 8 ounces (226g) quality semi-sweet chocolate, finely chopped
  • 2 cups (480g/ml) heavy cream, cold
  • 2 tablespoons confectioners’ sugar
  • 1/2 teaspoon pure vanilla extract

Chocolate Ganache Ingredients

  • 8 ounces (226g) quality semi-sweet chocolate, finely chopped
  • 1 cup (240g/ml) heavy cream
  • Optional garnish: fresh berries and/or chocolate shavings

Instructions

  1. Prepare pans and oven: Preheat oven to 350°F (177°C). Grease four 8- or 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper to ensure easy cake release.
  2. Mix dry ingredients: In a large bowl, whisk together flour, sugar, cocoa powder, espresso powder, baking soda, baking powder, and salt. Set aside.
  3. Mix wet ingredients: In a separate large bowl, whisk sour cream, oil, and eggs on medium-high speed until combined. Add buttermilk and vanilla extract, mixing until incorporated.
  4. Combine batter: Gradually add dry ingredients into wet mixture. Add hot water or coffee and beat on low speed until smooth. Fold in floured mini chocolate chips if using. Divide batter evenly between prepared pans.
  5. Bake cakes: Bake 19–23 minutes, or until a toothpick comes out clean. Cool in pans on racks for 1 hour, then loosen edges, remove cakes from pans, peel parchment, and cool completely.
  6. Make chocolate mousse: Whisk hot water and cocoa powder until smooth. Melt chopped chocolate using double boiler or microwave, then stir in cocoa mixture until thick and smooth. Whip cold heavy cream with confectioners’ sugar and vanilla to medium peaks. Fold chocolate mixture gently into whipped cream. Cover and refrigerate 2 hours or up to 2 days.
  7. Assemble cake layers: Level cake tops if needed. Place first cake layer on serving plate. Spread about 1.5 cups chocolate mousse evenly on top. Repeat with second (upside down), third (right side up) layers, each topped with mousse. Add final cake layer, spread remaining mousse over top and sides as crumb coat. Smooth with bench scraper and refrigerate 1-4 hours.
  8. Prepare chocolate ganache: Heat cream until gently simmering. Pour over chopped chocolate in bowl, let sit 2-3 minutes. Stir gently until smooth. Refrigerate 30 minutes to 1 hour to thicken.
  9. Finish cake: Pour or spoon thickened ganache over chilled cake, smoothing top and sides. Garnish with fresh berries or chocolate shavings if desired. Serve immediately or chill uncovered 4–6 hours before serving.
  10. Store leftovers: Cover leftover cake tightly and refrigerate up to 5 days.

Notes

  • Optional espresso powder enhances chocolate flavor but can be omitted.
  • Use room temperature ingredients for best cake texture.
  • Hot water or coffee added to batter intensifies chocolate taste.
  • Flour the mini chocolate chips to prevent sinking during baking.
  • Cocoa powder choice (natural vs Dutch process) affects cake acidity and texture.
  • Medium peaks for whipped cream means soft peak holds but still slightly droopy.
  • Chilling mousse allows it to firm up and makes assembly easier.
  • Do not overmix mousse once chocolate is added to keep it light and airy.
  • Chocolate ganache thickness depends on chilling time; do not overheat to avoid graininess.
  • Slicing cake layers flat improves stability and appearance.

Find it online: https://dishcooks.com/dark-chocolate-mousse-cake-recipe/