1. In a large bowl, whisk the yolks with the sugar and salt until
the mixture is pale. Stir in the lemon zest.
2. In a saucepan, heat the milk until almost boiling. Gradually
whisk the hot milk into the bowl containing the egg yolk mixture,
then cook the mixture over a double broiler until the cream coats
the back of a spoon (170°F). Strain into a bowl over ice;
stir to chill.
3. Add the vanilla and amaretto. Place in the refrigerator at
least 2 hours.
4. Pour into an ice cream maker and process. When the gelato
is ready stir in the crumbled cantucci. Place in a container,
cover and freeze for a minimum of 3 hours.