Meanwhile, put egg yolks and sugar in a bowl and beat with wire whisk until pale yellow and thick. Gradually pour hot milk into beaten yolks in thin stream, stirring constantly with whisk.

Return mixture to saucepan and place over medium-low heat. Cook, stirring constantly, until the custard thickens and coats the back of a spoon, 5 to 6 minutes. Do not let custard boil, or it will curdle.

Strain through a fine-mesh sieve into clean metal bowl. Cool completely over bowl of ice water. Cover and chill in refrigerator until cold. (Custard mixture can keep in refrigerator for a day or two.)

Freeze mixture in ice cream freezer according to manufacturer’s instructions. Serve immediately, or transfer to tightly sealed container and freeze for a day or two.