01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and lightly dust with flour, tapping out excess.
02 - Melt chocolate and butter together in a heatproof bowl set over a saucepan of barely simmering water, stirring until smooth. Remove from heat and let cool slightly.
03 - In a separate bowl, whisk eggs, egg yolks, and sugar until pale and thick, about 2-3 minutes.
04 - Stir the melted chocolate mixture into the egg mixture, then add vanilla and a pinch of salt. Sift in flour and fold gently until just combined.
05 - Divide batter evenly among prepared ramekins. Place ramekins on a baking sheet.
06 - Bake for 11-13 minutes, until edges are set but centers are still soft. Remove from oven and let stand for 1 minute.
07 - Combine raspberries, sugar, and lemon juice in a small saucepan. Cook over medium heat for 4-5 minutes until berries break down and sugar dissolves. Puree and strain through a fine sieve to remove seeds.
08 - Run a knife around the edges of each lava cake to loosen. Invert onto dessert plates. Dust with powdered sugar and garnish with fresh raspberries and mint if desired. Serve immediately with raspberry coulis.