Step 1 Preheat the oven to 325°F and set an oven rack in the middle position.
Step 2 In a medium saucepan, bring the cream to a gentle simmer, then immediately remove from the heat. Split the vanilla bean in half lengthwise and scrape out the seeds; add both the seeds and the pod to the cream and let sit for 15 minutes. (Alternatively, add the vanilla bean paste or vanilla extract.)
Step 3 Bring a kettle of water to a boil.
Step 4 In a large bowl, whisk the eggs yolks, sugar, and salt until well combined and slightly pale, about 1 minute.
Step 5 Over a medium bowl, strain the cream through a fine mesh strainer to remove any bits of the vanilla bean pod (skip this step if using vanilla bean paste or vanilla extract). Discard the bean pod. Gradually pour the warm cream into the egg mixture, a little at a time, whisking constantly. Transfer the mixture to a bowl with a pour spout or a large measuring cup.
Step 6 Place 4 (8-ounce) custard dishes or ramekins into a large roasting pan. Pour the custard mixture into the dishes or ramekins. Pour enough hot water from the kettle into the roasting pan to come about halfway up the sides of the custard dishes/ramekins. Carefully transfer the pan to the oven and bake for 30 to 40 minutes, or until the centers are just set. Carefully remove the pan from the oven and, using tongs or a wide spatula, remove the custards from the roasting pan. Refrigerate for least 2 hours and up to 3 days (cover them with plastic wrap if making more than a few hours ahead).
Step 7 Before serving, sprinkle each custard with 1½ to 2 teaspoons sugar, depending on the size of the custard dish. Use a blowtorch to caramelize the sugar until it is deeply golden but not burnt. Alternatively, place the custard dishes on a baking sheet and broil 2 to 3 inches from the heat source for a few minutes, or until the sugar melts and browns (keep a close eye to make sure they don't burn). Let sit for at least 5 minutes or up to 1 hour before serving.
