Scald cream, milk, and salt in a 3-quart saucepan over medium heat. Meanwhile, beat egg yolks and sugar to the “ribbon stage” (very thick and creamy) in a large, heat-proof bowl.
When milk mixture develops tiny bubbles around the outside of the saucepan, remove from heat and whisk a small amount into the egg yolk mixture. Keep whisking and gradually add all the hot mixture to eggs. Return to saucepan; reduce heat slightly. Stirring gently, cook until it registers 175º on a candy thermometer.
Pour cream of coconut into another heat-proof bowl. Remove heated mixture from stove and strain into the bowl. Add coconut flavoring and chopped coconut, if desired.
Chill in refrigerator until very cold (about four hours). You can reduce this time by chilling the mix in ice water for about 30 minutes and then refrigerating for about an hour. Freeze according to manufacturer’s instructions.