Stir both chocolates in top of double boiler over barely simmering water until melted. Add 1/3 cup hot water, corn syrup and extract; whisk until smooth. Remove from over water. Cool slightly. (Can be made 2 days ahead. Cover; chill. Before serving, rewarm in saucepan over low heat, stirring constantly.)
Vanilla ice cream
Preheat oven to 450° F. Butter six 3/4-cup souffl? dishes or custard cups.
Stir chocolate and butter in heavy medium saucepan over low heat until melted. Cool slightly. Whisk eggs and egg yolks in large bowl to blend. Whisk in sugar, then chocolate mixture and flour. Pour batter into dishes, dividing equally. (Can be made 1 day ahead. Cover; chill.)
Bake cakes until sides are set but center remains soft and runny, about 11 minutes or up to 14 minutes for batter that was refrigerated. Run small knife around cakes to loosen. Immediately turn cakes out onto plates. Spoon sauce around cakes.
Serve with ice cream.Makes 6 Source: