01 - Preheat oven to 425°F (220°C). Liberally butter four 6-ounce ramekins, then dust generously with cocoa powder, ensuring to tap out any excess.
02 - Combine the finely chopped chocolate and butter in a heatproof bowl set over a saucepan of simmering water (bain-marie). Stir gently until fully melted and smooth, then remove from heat and allow to cool slightly.
03 - In a separate mixing bowl, vigorously whisk the whole eggs, egg yolks, and granulated sugar until the mixture becomes pale, thick, and achieves a ribbon consistency, approximately 2 minutes.
04 - Gently fold the slightly cooled melted chocolate mixture and vanilla extract into the whipped egg mixture until just combined.
05 - Sift the all-purpose flour and fine sea salt directly into the batter. Carefully fold until the flour is just incorporated, taking care not to overmix.
06 - Evenly distribute the prepared batter among the four buttered and floured ramekins. Arrange the filled ramekins on a baking sheet.
07 - Bake for 12 minutes, or until the edges of the cakes are visibly set but the centers remain soft and molten.
08 - While the cakes are baking, prepare the raspberry sauce. In a small saucepan, combine the fresh or frozen raspberries, granulated sugar, and freshly squeezed lemon juice. Cook over medium heat for 4–5 minutes, stirring and gently mashing the berries until they break down and the sauce achieves a slight thickening. For a smoother consistency, strain the sauce through a fine mesh sieve to remove seeds, if preferred.
09 - Carefully remove the baked cakes from the oven and allow them to rest in their ramekins for 1 minute. Using a thin knife, gently loosen the edges of each cake, then invert onto individual dessert plates.
10 - Generously drizzle each lava cake with the prepared raspberry sauce. Lightly dust with powdered sugar. Serve immediately, optionally garnished with fresh raspberries and accompanied by vanilla ice cream or whipped cream.