Preheat oven to 425°F. Butter 6 (6-ounce) custard cups or soufflé dishes. Place on baking sheet.
Microwave chocolate and butter in large microwavable bowl on HIGH 1 minute or until butter is melted. Stir with wire whisk until chocolate is completely melted. Stir in raspberry flavor and vanilla. Stir in sugar until well blended. Whisk in eggs and yolk. Stir in flour. Pour batter into prepared custard cups.
Bake 10 to 14 minutes or until sides are firm but centers are soft. Let stand 1 minute. Carefully loosen edges with small knife. Invert cakes onto serving plates.
For the Raspberry Sauce, mix raspberries and raspberry extract until well blended. Serve with cakes.