03In a small saucepan, scald milk and set aside.04In a bowl, beat egg yolks well. Beat in sugar, salt and spices. Add hot milk slowly, whisking constantly. Pour mixture into the top of a double boiler and cook over barely simmering water, stirring constantly, 5 to 8 minutes or until mixture coats the back of a spoon.05Turn off the heat, whisk in the potato puree. Cool to room temperature; stir in cream and vanilla. Chill in the refrigerator for at least 1 hour. Freeze in an ice-cream maker according to manufacturer's directions. Fold in nuts, if desired.