01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and dust with flour, tapping out excess. Place on a baking sheet.
02 - Set a heatproof bowl over a pot of simmering water. Add chopped chocolate and butter, stirring constantly until completely smooth and melted. Remove from heat and cool slightly.
03 - In a separate bowl, whisk eggs, egg yolks, and granulated sugar until thick, pale, and doubled in volume, about 2 minutes.
04 - Gently fold the warm chocolate mixture into the egg mixture. Stir in vanilla extract and salt until incorporated.
05 - Sift flour over the batter and fold gently until just combined. Do not overmix.
06 - Divide batter evenly among the prepared ramekins, filling each about three-quarters full.
07 - Bake for 11 to 13 minutes until edges are firm and set but centers still jiggle slightly. The tops should be puffed and slightly cracked.
08 - While cakes bake, combine raspberries, sugar, lemon juice, and water in a small saucepan over medium heat. Cook for 4 to 5 minutes, mashing berries and stirring frequently until thickened. Strain through a fine mesh sieve if desired.
09 - Let cakes cool for exactly 1 minute. Run a thin knife around the edges to loosen, then invert each cake onto individual serving plates.
10 - Spoon warm raspberry sauce over each molten cake. Dust generously with powdered sugar, garnish with fresh raspberries, and serve immediately with vanilla ice cream or whipped cream.