Preparation Steps

• Preheat your oven to 350°F (175°C). Grease and line a 9-inch springform pan with parchment paper.
• In a heatproof bowl set over a saucepan of simmering water (double boiler), melt the chopped dark chocolate and butter together, stirring until smooth.
  226 grams dark chocolate
• Remove the bowl from the heat and whisk in the granulated sugar until well combined. Let the mixture cool slightly.
  226 grams dark chocolate
• In a separate bowl, whisk together the egg yolks, salt, and vanilla extract. Gradually whisk this mixture into the cooled chocolate mixture.
  226 grams dark chocolate
• In a clean bowl, beat the egg whites until stiff peaks form.
• Gently fold about a third of the whipped egg whites into the chocolate mixture to lighten it. Then, carefully fold in the remaining egg whites until just combined. Do not overmix.
• Pour the batter into the prepared springform pan and smooth the top.
• Bake for 30-35 minutes, or until the edges are set and the center is still slightly soft. A toothpick inserted into the center should come out with moist crumbs, not wet batter.
• Let the cake cool in the pan on a wire rack for 10 minutes before releasing the sides of the springform pan. Allow to cool completely on the rack.