Melt the butter in a 12-inch nonstick skillet over high heat. Add the Barbecue Magic and stir for about 1 minute. Add the tomato sauce and stir until combined. Cook for 2 minutes, then add the stock, vinegars, Magic Pepper Sauce and Worcestershire. Stir well and bring just to a boil, stirring constantly, then reduce the heat to medium and simmer stirring occasionally until the sauce thickens and resembles a thin ketchup, about 25 minutes. Add the liquid smoke and brown sugar and stir until the sugar is dissolved. Remove from the heat and serve.