Rich Chocolate Layer Cake with Chocolate Mousse

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A decadent chocolate cake featuring moist chocolate sponge layers filled and frosted with silky chocolate mousse, perfect for special occasions.

Ingredients (6-inch round cake)

For the Chocolate Sponge Cake:

  • Whole eggs: 155g (3 large eggs)
  • Granulated sugar: 90g
  • Honey: 15g
  • Cake flour: 70g
  • Cocoa powder: 25g (Dutch-process recommended)
  • Unsalted butter: 30g
  • Whole milk: 30g
  • Salt: 1g
  • Vanilla extract: 4ml

For the Chocolate Mousse:

  • Dark chocolate (60-70% cacao): 200g
  • Heavy whipping cream: 400ml (cold)
  • Powdered sugar: 30g
  • Vanilla extract: 3ml

For the Simple Syrup:

  • Water: 50ml
  • Granulated sugar: 25g
  • Coffee or liqueur: 10ml (optional)

For Decoration:

  • Fresh raspberries: 6-8 berries
  • Dark chocolate curls or shavings
  • Cocoa powder for dusting (optional)

Instructions

Make the Chocolate Sponge Cake

  1. Preheat oven to 175°C (350°F). Line a 6-inch round pan with parchment paper
  2. Sift together cake flour and cocoa powder twice
  3. Melt butter with milk and keep warm at 55-60°C
  4. Place eggs, sugar, salt, and honey in a bowl over a double boiler
  5. Warm to 40-42°C, stirring constantly with a whisk
  6. Remove from heat, add vanilla extract
  7. Whip on high speed until pale, thick, and voluminous (ribbon stage - about 5-7 minutes)
  8. Finish on low speed for 1-2 minutes to stabilize bubbles
  9. Fold in warm milk gently with a spatula
  10. Add flour-cocoa mixture in two additions, folding gently until no streaks remain
  11. Take a small portion of batter and mix into the warm butter-milk mixture
  12. Fold this back into main batter quickly and smoothly
  13. Pour into prepared pan, tap firmly on counter to release air bubbles
  14. Bake at 165°C for 30-35 minutes until a toothpick comes out clean
  15. Remove from oven, tap pan to release steam
  16. Invert onto a cooling rack and cool completely

Make the Simple Syrup

  1. Combine water and sugar in a small pot, heat until sugar dissolves
  2. Remove from heat, add coffee or liqueur if using
  3. Cool completely

Make the Chocolate Mousse

  1. Chop dark chocolate into small pieces
  2. Melt chocolate using a double boiler or microwave (in 20-second intervals)
  3. Let cool to room temperature but still pourable (about 30°C)
  4. In a chilled bowl, whip heavy cream, powdered sugar, and vanilla to soft peaks
  5. Take 1/3 of whipped cream and fold into melted chocolate to lighten it
  6. Gently fold chocolate mixture back into remaining whipped cream until combined
  7. Use immediately or refrigerate for 15-20 minutes if too soft

Assemble the Cake

  1. Level the top of the cooled cake if domed
  2. Slice cake horizontally into 3 equal layers (about 1.5cm each)
  3. Place bottom layer on a cake board or plate
  4. Brush with simple syrup (don't oversoak)
  5. Spread about 4-5 tablespoons of chocolate mousse evenly
  6. Place second layer on top, brush with syrup
  7. Spread another layer of chocolate mousse
  8. Place final layer on top, brush with syrup
  9. Apply a thin crumb coat of chocolate mousse over entire cake
  10. Refrigerate for 30 minutes to set
  11. Apply final smooth layer of chocolate mousse
  12. Use a spatula or bench scraper for smooth sides
  13. Refrigerate for at least 2 hours before decorating

Tips

  • Use high-quality chocolate for the best flavor
  • Don't overwhip the cream for mousse - it should be silky, not grainy
  • Slice cake with a warm, clean knife for neat cuts
  • The chocolate mousse firms up in the fridge, making it easier to frost
  • Let cake sit at room temperature for 20-30 minutes before serving for optimal texture

Storage

Refrigerate for up to 3 days. Best enjoyed within 2 days.