01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and dust with cocoa powder, tapping out excess.
02 - In a heatproof bowl set over a pan of simmering water, melt chocolate and butter together, stirring until smooth. Remove from heat and let cool slightly.
03 - In a medium bowl, whisk eggs, egg yolks, and sugar until pale and thickened, approximately 2 minutes.
04 - Pour the melted chocolate mixture into the egg mixture, whisking gently until fully incorporated.
05 - Sift flour and salt into the batter, folding together until just combined. Do not overmix.
06 - Divide batter evenly among prepared ramekins. Place ramekins on a baking tray for stability.
07 - Bake for 12 minutes, until edges are firm but centers still appear slightly soft. Remove from oven and cool for 1 minute.
08 - While cakes bake, combine raspberries, sugar, lemon juice, and water in a small saucepan. Cook over medium heat, stirring occasionally, until raspberries break down and sauce thickens, 5–7 minutes. Strain through fine sieve if seedless sauce is preferred.
09 - Run knife around cake edges, invert onto serving plates, and remove ramekins. Drizzle with raspberry sauce, dust with powdered sugar, and garnish with fresh raspberries and whipped cream or ice cream if desired.