Add the cream and wine to a saucepan and heat over medium heat. Cook until the liquid is warm and there are bubbles forming on the edges of the pot, about 3 minutes. Stir in the sugar until it is totally dissolved and allow the mixture to come to a boil. Reduce the heat to low and stir in the butter until melted. Turn off the heat and add in the chocolate, allowing it to sit for a minute. Then stir constantly until the chocolate is completely melted. Stir in the vanilla extract and salt. You can use it right away, but I like to let this sit for an hour at room temperature to thicken even more.
Recipe courtesy of Jessica Merchant