Ingredients:

  • 2 Large Eggs, separated (for Base)
  • 1/4 cup Granulated Sugar, divided (for Base)
  • 1/4 cup All-Purpose Flour, sifted (for Base)
  • 2 tbsp Unsweetened Cocoa Powder (for Base)
  • 12 oz Dark Chocolate (70% Cacao), finely chopped (for Mousse)
  • 2 cups Heavy Cream, cold (for Mousse)
  • 4 Large Eggs, yolks only (for Mousse)
  • 1/4 cup Granulated Sugar (for Mousse)
  • 1/4 cup Water (for Mousse Gelatine)
  • 2 tsp Unflavored Gelatine Powder (for Mousse)
  • 1 tsp Unflavored Gelatine Powder (for Glaze)
  • 1/4 cup Water (for Glaze)
  • 1/2 cup Granulated Sugar (for Glaze)
  • 1/2 cup Heavy Cream (for Glaze)
  • 1/4 cup Unsweetened Cocoa Powder, sifted (for Glaze)

Instructions:

  1. Phase 1: The Chocolate Sponge Base. Beat egg whites to stiff peaks, gradually adding half the sugar. In a separate bowl, whisk egg yolks and remaining sugar until pale and thick. Gently fold the yolk mixture into the whites.
  2. Sift together the flour and cocoa powder. Gently fold the dry mix into the egg mixture until just combined.
  3. Spread the batter thinly onto a parchment-lined baking sheet. Bake at 350°F (175°C) for 12–15 minutes, or until set.
  4. Cool completely. Use a 9-inch (23 cm) cake ring/base as a template and cut out a perfect circle from the cooled sponge. Place the sponge at the bottom of the clean, parchment-lined cake ring.
  5. Phase 2: The Dark Chocolate Mousse. Sprinkle 2 tsp of gelatine powder over 1/4 cup of cold water and let it bloom for 5 minutes.
  6. Melt the chopped dark chocolate gently over a double boiler or in the microwave until smooth. Set aside to cool slightly.
  7. Whisk the 4 egg yolks and 1/4 cup sugar vigorously until light. Heat the bloomed gelatine gently until liquid (do not boil). Slowly whisk the melted gelatine into the egg yolk mixture.
  8. Pour the slightly cooled melted chocolate into the egg/gelatine mixture and stir until fully homogenous.
  9. In a separate, cold bowl, whip the 2 cups of heavy cream to medium-soft peaks.
  10. Gently fold one-third of the whipped cream into the chocolate mixture to lighten it. Then, gently fold in the remaining cream in two additions, using broad, careful movements. Stop immediately when no streaks remain.
  11. Immediately pour the mousse over the sponge base in the prepared cake ring and smooth the top. Chill in the refrigerator for at least 4 hours, or until the mousse is firm to the touch.
  12. Phase 3: The Mirror Glaze and Finish. Bloom the glaze gelatine (1 tsp) in 2 tablespoons of water.
  13. Combine the remaining water, sugar, cream, and sifted cocoa powder in a small saucepan. Bring to a rolling boil over medium heat, stirring constantly until smooth. Remove from heat.
  14. Stir the bloomed gelatine into the hot syrup until completely dissolved.
  15. Allow the glaze to cool to 90–95°F (32–35°C).
  16. Place the chilled cake on a wire rack set over a baking sheet. Pour the glaze slowly and evenly over the center of the cake, allowing it to flow naturally over the sides.
  17. Refrigerate for another 2 hours to allow the glaze to set. Carefully run a thin, hot knife around the edge before removing the cake ring and transferring to a serving plate.