Green Tea Ice Cream

Bring cream, milk, and salt to a boil in a 3- to 4-quart heavy saucepan and remove from heat. Whisk together eggs, sugar, and matcha in a bowl (tea will not be completely dissolved), then add 1 cup hot cream mixture in a slow stream, whisking vigorously. Whisk custard into remaining cream mixture in saucepan and cook over moderately low heat, stirring constantly with a wooden spoon, until thick enough to coat back of spoon and registers 170 °F on an instant-read thermometer (do not let boil). Immediately pour custard through a fine sieve into a metal bowl, then cool to room temperature, stirring occasionally. Chill, covered, until cold, at least 1 hour. Freeze in ice cream maker, then transfer to an airtight container and put in freezer to harden.