01 - Preheat oven to 350°F. Grease an 8-inch round springform pan and line the base with parchment paper.
02 - Place chopped dark chocolate and butter in a heatproof bowl over simmering water. Stir until smooth, then remove from heat.
03 - Whisk sugar, sea salt, and vanilla extract into the melted chocolate mixture until evenly combined.
04 - Add eggs one at a time, whisking thoroughly after each addition until mixture is glossy and thick.
05 - Pour batter into the prepared pan and smooth the surface evenly.
06 - Bake for 25 to 30 minutes until the edges are set and the center remains slightly wobbly.
07 - Let the cake cool completely in the pan on a wire rack, approximately 1 hour. The center will sink slightly.
08 - Remove sides of springform pan and transfer cake to a serving plate. Top with fresh raspberries.
09 - Dust with powdered sugar before serving if desired.