In a metal bowl whip egg yolks and sugar until fluffy.

In a metal bowl over a pan of boiling water on the stove (or use your double boiler) warm 2 cups of cream. (do not boil)

Add warm cream in a slow stream to egg mixture, whisking constantly. This is the custard.

Set the custard mixture in a metal bowl over boiling water (or use double boiler)

Stir custard with a wooden spoon constantly, until thermometer reaches 170 degrees.

Remove from the heat and stir in the remaining cup of cream, place in the refrigerator to cool for about an hour.

When the custard is cool, add vanilla and grape nuts and pour it into your ice cream maker.

Freeze according to your maker’s instructions.

Pour into a metal loaf pan, cover, and place in your freezer until frozen.