1. In a medium saucepan, mix half-and-half and heavy cream.
2. Heat over medium flame until lightly simmering, then remove from heat. DO NOT BOIL.
3. In a medium mixing bowl, add egg yolks and whisk until they turn a light golden yellow. Whisk in sugar until blended.
4. Into the yolk mixture, slowly stir in cream & half-and-half until well blended.
6. Pour the entire mixture back into the saucepan and place over low flame.
7. Continue to heat, stirring frequently, until mixture slightly thickens to coat the back of a spoon.
8. Pour mixture into a large bowl and allow to cool to room temperature.
9. Stir in vanilla extract.
10. Cover mixture and allow to chill thoroughly in the refrigerator before placing into an ice cream maker. Process according to manufacturer's directions, about 25 - 30 minutes.
Serve soft, or freeze for several more hours for hard ice cream.