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