Grease eight 6 ounce (175 mL) ramekins; line bottoms with parchment paper.
Set ramekins aside.
In large bowl over saucepan of hot (not boiling) water, melt chocolate with
butter until smooth; set aside.
In another heatproof bowl over saucepan of gently simmering water, whisk
egg yolks with 1/2 cup (125 mL) of the sugar; cook, whisking constantly, until
light and thickened, about 8 minutes. Fold one-quarter into chocolate mixture;
fold in remaining yolk mixture. Set aside.
In large bowl, beat egg whites until soft peaks form; beat in remaining
sugar, 2 tablespoons (25 mL) at a time, until stiff peaks form. Fold cocoa and
one-third of the egg whites into chocolate mixture; fold in remaining egg whites.
Spoons into prepared ramekins. Bake in center of oven until puffed and edges
are set, about 20 minutes. Make-ahead: Cover and refrigerate for up to 1 day.
Invert cakes onto dessert plates; remove paper. Garnish each plate with
raspberry sauce; top with scoop of raspberry sorbet.
Raspberry Sauce: In blender or food processor; pulse together raspberries,
water, sugar and lemon juice until smooth; press through fine sieve to remove
Yield: 8 servings; 1 1/2 cups sauce
Make-ahead: Refrigerate in airtight container for up to 1 week.