Classic Custard Sauce

Directions

1. 1
   In the bottom of a double boiler, bring one inch of water (water must not touch top pan) to simmer over medium heat.
2. 2
   In the top of a double boiler, beat together egg yolks, sugar, and salt until thick and light-colored. Gradually add half-and-half.
3. 3
   Heat, stirring constantly, until mixture is somewhat thickened and coats a spoon. (Mixture must not come to a boil or it will curdle.).
4. 4
   Remove from heat; add sherry or brandy or vanilla. Chill.