Ingredients:

  • 8 ounces (225 grams) Dark Chocolate (70% Cacao minimum)
  • 8 ounces (225 grams) Unsalted Butter, cut into cubes
  • 1 cup (200 grams) Granulated Sugar, divided
  • 5 large Eggs, separated, at room temperature
  • 1 teaspoon Vanilla Extract
  • 1 teaspoon Espresso Powder (optional)
  • 1/4 teaspoon Fine Sea Salt

Instructions:

  1. Preheat oven to 350°F (175°C). Grease the 9-inch springform pan bottom, line with a parchment circle, and grease the parchment.
  2. Create a gentle double boiler (bain-marie). Combine the chopped chocolate and cubed butter in the heatproof bowl over simmering water. Stir frequently until completely smooth. Remove from heat, stir in vanilla and espresso powder (if using). Set aside to cool slightly.
  3. In a separate bowl, lightly whisk the 5 egg yolks with half the sugar (1/2 cup) until pale and slightly thickened.
  4. Gradually whisk the slightly cooled chocolate mixture into the yolk mixture until fully incorporated, forming the rich base batter.
  5. In a clean, grease-free mixer bowl, beat the 5 egg whites with the salt until soft peaks form. Gradually stream in the remaining 1/2 cup of sugar while beating until stiff, glossy peaks form.
  6. Gently fold one-third of the stiff egg whites into the chocolate base batter to lighten it. Then, carefully fold in the remaining egg whites in two additions using a cut-and-fold motion to retain air.
  7. Pour batter into the prepared pan. Bake for 40–45 minutes. The edges should look set, but the centre should still wobble slightly.
  8. Let the cake cool completely on a wire rack, then chill in the refrigerator for at least 2 hours before unmoulding and serving.