English Cream with Vanilla, Lemon or Orange Zest

Beat in a saucepan half a pound of sugar with ten raw egg-yolks; mingle both well together and dilute with a quart of boiling milk, having had half a vanilla stick broken in pieces infused therein. Cook the cream on a moderate fire, stirring with a spoon or whisk and thicken without boiling; strain this through a fine sieve into a vessel and let cool, stirring it occasionally until this occurs. This cream can be flavored with lemon or orange peel instead of vanilla.