In a small heavy saucepan bring half-and-half just to a boil with vanilla bean and ginger and remove pan from heat. Scrape seeds from vanilla bean with a knife into pan, reserving pod for another use.
While half-and-half mixture is heating, in a bowl with an electric mixer whisk together eggs and sugar until light and fluffy. Add hot half-and-half mixture in a stream, beating, and transfer to a saucepan. Cook custard over moderately low heat, stirring constantly with a wooden spoon, until thickened (170 degrees F on a candy thermometer), but do not let it boil, and strain through a fine sieve into metal bowl. Set bowl in a larger bowl of ice and cold water and cool sauce, stirring occasionally. Chill sauce, covered, at least 2 hours, or until very cold. Creme anglaise may be made 2 days ahead and chilled, covered.
Recipe courtesy of Gourmet Magazine