In a large saucepan, whisk together the eggs, sugar and salt, if using. Add half the milk. Cook over low heat, stirring constantly, until the mixture coats the back of a metal spoon and has reached 160o F. Remove from heat. Add the remaining milk and the vanilla. Cover and refrigerate several hours or overnight, until thoroughly chilled. Just before serving, pour into a bowl or pitcher. Garnish, if desired, with one or more of the following: chocolate shavings, cinnamon sticks, aromatic extracts, fruit juice or nectar, ground nutmeg, maraschino cherries, orange slices, peppermint sticks, sorbet or ice cream, whipped cream. Serve immediately.