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