This recipe is from Meredith Kurtzman, "Otto" restaurant. It was printed in the June 2, 2003 issue of NY Magazine ("Italian Summer Pleasures from Antipasto to Gelato"). The Prep time includes all chilling/freezing times.
Put the lemon zest and vanilla bean in a bowl, and add the hot milk.
When cool, cover and allow to infuse for about 8 hours or overnight in the refrigerator.
Strain the milk into a sauce pan, add half the sugar, and bring to a simmer.
Whisk the egg yolks with the remaining sugar until combined.
Gradually dribble the hot milk into the egg yolks, half a cup at a time, whisking to heat the yolks without cooking them.
When all the milk has been added, cook the mixture over medium heat, stirring continuously, for about 4 to 5 minutes or until the mixture is thick enough to coat the back of a spoon and leave a trail when a finger is run over the spoon (Don't overcook the eggs; doing so will change the flavor of the gelato).
Stir in a pinch of salt, and straininto a heatproof bowl set over ice.
Cover, and refrigerate for at least 6 hours or overnight.
Transfer mixture to an ice cream machine, and process according to directions.
Transfer gelato to a container and return to freezer for about 2 hours.