Forgotten Chocolate Soufflé

Ingredients

• 12 ounce bittersweet chocolate, chopped
• 1/2 cup butter, cut into tablespoon pieces
• 1 vanilla bean, cut lengthwise
• 1/4 teaspoon salt
• 12 tablespoon sugar
• 5 eggs, separated, at room temperature for thirty minutes
• 1/4 cup all-purpose flour
• pinch of salt