Beat eggs, sugar, salt, cinnamon and nutmeg together in a large saucepan. Stir in half the milk (3 cups). Cook on medium - low heat, being careful not to scorch, cook, stirring constantly until mixture is thick, and it thinly coats a spoon. Remove from heat and mix in the remaining milk and vanilla. Put in a container with tight fitting lid. Cover and chill overnight or until ready to use.
*** Serve the eggnog with a dollop of whip cream and a light dusting of cinnamon and nutmeg (optional).