Remove from the heat, cover, and steep for 30 minutes.
Whisk the egg yolks with sugar and salt until pale and fluffy.
Strain the infused dairy through a fine-mesh strainer
Gradually temper the milk into the yolk mixture.
Return to medium heat, stirring constantly until the mixture reaches 180 F and coats the back of a spoon.
Strain the custard through a fine-mesh sieve into a bowl set over ice bath.
Stir in the lemon juice.
Once cooled to room temperature, cover and refrigerate for 8 hours or overnight.
Whisk the limoncello, lemon extract, and glucose syrup into the chilled base.
Process in a pre-chilled ice cream machine according to the manufacturer's instructions until it reaches an internal temperature of 23 F, approximately 20-25 minutes.
Transfer to a chilled container.
Freeze for a minimum 4 hours before serving or preferably 24 hours for optimal flavor development.
Allow the gelato to rest for 10 minutes at room temperature before serving.