Preheat the oven to 325 degrees F.
Pour the cream and wine into a small pot and place over medium-low heat.
Cook until the liquid is steaming and small bubbles have formed around the edges.
Add the chocolate, stirring occasionally, until smooth and melted.
Whisk the egg yolks, sugar, and salt together in a mixing bowl.
Pour a little of the hot cream mixture over the yolks, whisking to warm them.
Continue adding warm liquid to the yolks, a little at a time, whisking after each addition.
When all the liquid has been added, stir in the vanilla and strain the mixture through a fine mesh sieve into a spouted vessel.
Divide equally between four demitasse cups.
Place the demitasse cups in a larger baking dish. Fill the larger dish with hot water, halfway up the sides of the cups.
Bake for 42-48 minutes, or until set around the edges and just barely wobbly towards the centers.