A variety of other sauces could be used in place of the caramel sauce – warm chocolate fudge, raspberry puree or even vanilla crème anglaise.
Preheat the oven on the Convection Mode at 375 °F. Using a medium bowl set over a pot of simmering water, melt the chocolate and butter. Remove from the heat and add the vanilla. Whisk in one egg yolk at a time. Set aside. In the mixing bowl of a stand mixer, combine the egg whites, sugar, salt and cream of tartar. Using the wire whip, mix on medium high speed until stiff peaks form. Gently fold the whipped egg whites into the melted chocolate. Melt 4 tablespoons of butter. Brush 10 six-fluid-ounce ramekins with melted butter. Sprinkle each ramekin’s bottom and sides with sugar. You will likely not need all the sugar. Turn each ramekin over a sink or bowl, to pour out sugar that did not stick. Divide the soufflé batter evenly between the 10 ramekins.
Place the ramekins on the solid pan. Place the solid pan in the preheated oven on rack position 2. Bake for 15 minutes or until set. Carefully remove the tray from the oven and gently tap the top of each soufflé with a spoon to break a small hole. Pour 1 tablespoon of caramel into each soufflé and serve.