Preheat oven to 425°F. Lightly grease 4 (6 oz) ramekins. Place on a baking sheet.
Microwave chocolate and butter in a large microwavable bowl for 1 minute, or until butter is melted. Stir with a wire whisk until chocolate is completely melted. Stir in wine, vanilla and icing sugar until well blended. Stir in eggs, egg yolk and flour. Divide batter evenly between prepared ramekins.
Bake 13 to 15 minutes in preheated oven, until sides are firm but centers are soft. Let sit 1 minute. Run a knife around edges to loosen. Invert cakes onto small serving plates. Sprinkle with additional icing sugar and garnish with fresh fruit if desired. Serve immediately.