Beat egg yolks in top of double boiler until thick and lemon colored; gradually add sugar and salt, beating until smooth. Slowly add half-and-half to egg mixture, beating constantly. Place over boiling water, stirring constantly, until custard thickens and coats a spoon. Remove from heat; chill 2 hours.
Pour mixture into freezer can of a 1-gallon hand-turned or electric freezer. Freeze according to manufacturer's instructions. Let ripen 1 hour before serving.