01 - Preheat oven to 350°F. Grease an 8-inch round springform pan and line the base with parchment paper.
02 - Combine chopped chocolate and cubed butter in a heatproof bowl. Melt over simmering water, stirring until smooth. Remove from heat and cool slightly.
03 - Whisk in granulated sugar and sea salt until fully blended.
04 - Add eggs one at a time, whisking thoroughly after each. Stir in vanilla extract until batter is glossy and thick.
05 - Pour the batter into the prepared pan and smooth the surface with a spatula.
06 - Bake for 25 to 30 minutes, until edges are set and center remains slightly soft. A toothpick inserted should come out with moist crumbs.
07 - Allow the cake to cool completely in the pan on a wire rack. Once cooled, remove from the pan and place on a serving plate.
08 - Top with fresh raspberries and dust with icing sugar if desired. Serve at room temperature.