In a mixing bowl, beat the egg yolks, sugar, and vanilla until smooth and fully blended. In a saucepan, heat the milk (do not boil). When hot (steaming), add the egg mixture slowly, whisking continuously. Reduce heat to low, and cook until it becomes a smooth custard, stirring to keep from boiling. Note: Alternatively, use a doubleboiler. Remove custard from the heat and set aside to cool.
When completely cooled, whip the cream to stiff peaks and gently fold into the custard mixture with a spatula.Transfer to an ice cream maker and freeze according to directions.
Without an ice cream maker: Pour into a metal container (baking pan works well), cover with lid or foil, and freeze for one hour. Remove, break up with a metal spoon, transfer to a mixing bowl and beat with an electric mixer (30 seconds) or whisk briskly until smooth, and freeze again. Repeat after another hour. Freeze for 3 hours before serving or packing into smaller closed containers.Additions: When adding dry pieces of chocolate, cereal, cookie pieces, etc., stir them just before adding to the ice cream freezer, or after the first freeze if using the old-fashioned method.