Preheat the oven to 325 degrees. In a saucepan, combine the cream, vanilla bean, and salt. Heat the mixture over low heat until it is just hot. Allow it to sit for a few minutes, then remove and discard the vanilla bean. If you're using vanilla extract, add it at this point.

In a bowl, beat the egg yolks and sugar until they become light in texture. Stir in about a quarter of the vanilla cream into this mixture. Then, pour the sugar-egg mixture into the cream and mix. Divide the mixture evenly into four 6-ounce ramekins and arrange them in a baking dish. Fill the dish with boiling water, ensuring it reaches halfway up the sides of the ramekins.

Bake the custards for 30 to 40 minutes or until the centers are barely set. Allow them to cool completely, then refrigerate for several hours or up to a few days.

Before serving, sprinkle about a teaspoon of sugar evenly over the surface of each custard.

Position the ramekins in a broiler, about 2 to 3 inches from the heat source. Turn on the broiler and cook until the sugar has melted and caramelized to your liking, approximately 5 minutes. Serve the custards within 2 hours for optimal enjoyment.