4 squares semi-sweet baking chocolate
PREHEAT oven to 425°F. Butter four 3/4-cup custard cups or soufflé dishes. Place on baking sheet.
MICROWAVE chocolate and butter in large microwaveable bowl on HIGH 1 min. or until butter is melted. Stir with wire whisk until chocolate is completely melted. Stir in sugar until well blended. Blend in eggs and egg yolks with wire whisk. Stir in flour. Divide batter among prepared custard cups.
BAKE 13 to 14 min. or until sides are firm but centers are soft. Let stand 1 min. Carefully run small knife around cakes to loosen. Invert cakes onto dessert dishes. Serve immediately, topped with whipped topping.
Batter can be made a day ahead. Prepare batter as directed; pour into prepared custard cups. Cover with plastic wrap. Refrigerate up to 24 hours. Let stand at room temperature 1 hour before baking as directed.