Set a mesh strainer over a heat-resistent bowl.
1. Place the sugar and zest in your food processor and blitz until well blended—30–40 seconds.
2. Combine the sugar mixture, milk, cream, and lemon juice in a heavy-bottomed saucepan.
3. Turn the heat to medium and stir until the mixture is hot but not boiling.
4. Whisk the eggs and egg yolks together in a spacious, heat-tolerant bowl. Temper them by slowly adding one cup of the hot cream mixture while whisking vigorously.
5. Reduce the heat to medium-low and whisk the tempered eggs into the saucepan, creating custard. Stir constantly until the custard thickens slightly.
6. Strain the custard through a mesh strainer into a heat-resistent bowl.
7. Allow the custard to cool to room temperature (approximately 1 hour).
8. Refrigerate the mixture for 4–6 hours, or overnight.
9. Place the cold custard in the canister of your ice cream maker and process according to the manufacturer’s instructions. The ice cream will be soft.
10. Transfer the ice cream to a container, cover, and freeze for at least 4-6 hours to firm up.