In a medium saucepan, combine the whole milk and heavy cream. Heat over medium heat until just steaming, but not boiling.

In a separate bowl, whisk together the sugar and lemon zest.

Gradually stir the sugar mixture into the milk mixture until the sugar is fully dissolved.

Remove from heat and stir in the limoncello.

Chill the mixture in the refrigerator for at least 2 hours until very cold.

Pour the chilled mixture into an ice cream maker and churn according to the manufacturer's instructions.

Transfer the gelato to an airtight container and freeze for at least 2 hours or until firm before serving.