Place the half-and-half and the vanilla bean in the top of a double boiler. Heat
to the boiling point, then remove from heat and remove the vanilla bean. Slit the
bean open and scrape the seeds out into the half-and-half. (At this point you can
dry off the bean and use it to flavor granulated sugar.)
Beat eggs with a fork, then add sugar and salt. Mix well, and add a few tablespoons
of hot half-and-half to warm the eggs.
Put half-and-half back over barely simmering
water and stir in the warmed egg mixture. Continue to cook, stirring constantly,
until the custard coats spoon. Remove pan from the heat and press a sheet of wax
paper or plastic wrap onto the surface of the custard to keep a film from forming.