Method

1. Preheat oven to 325°F.
2. Lightly coat six 6-ounce ramekins or custard cups with cooking spray and set them on a kitchen towel in a deep baking pan. Set aside.
3. In a nonreactive saucepan, combine the milk and cream with 1/4 cup sugar and bring to a simmer over medium heat. Remove from heat and keep warm.
4. In a heavy saucepan, heat 1/4 cup of the sugar over medium heat until the sugar liquefies and turns a deep golden brown, about 4 to 5 minutes.
5. Add the hot cream/milk mixture to the caramel in 1/3 portions, bringing each addition to a boil while stirring constantly to dissolve, about 5 minutes total.
6. Add the melted chocolate to the mixture and stir briefly to blend.
7. Strain the cream mixture into a clean saucepan and return to a slow simmer.
8. In a heatproof bowl, whisk together the egg, egg yolks and the remaining 1/4 cup sugar.
9. Gradually add about 1/3 of the hot cream mixture to the eggs, whisking constantly.
10. Add the tempered egg mixture to the remaining cream mixture and stir to create a smooth custard.
11. Add vanilla to the custard mixture and stir.
12. Strain mixture into the prepared ramekins, filling each about 3/4 full.
13. Place the baking pan on a pulled-out oven rack. Add enough boiling water to the pan to come halfway up the sides of the ramekins. Cover the pan loosely with parchment paper or aluminum foil and bake at 325˚F until the pots de crème are very glossy on top and jiggle only slightly when shaken, about 20 to 25 minutes.
14. Remove the ramekins from the water bath and place on a rack to cool for 30 minutes.
15. Wrap individually and refrigerate at least 3 hours (or up to 3 days) before serving.