½cupfreshly squeezed lemon juicefrom about 3 medium lemons
In a small saucepan, simmer milk and ¼ cup of sugar over medium low heat. Do NOT boil the milk.
In a separate bowl, beat the egg yolks with remaining ¼ cup of sugar, salt and lemon zest until nice and pale. To temper the egg yolk mixture, ladle some warm milk and whisk vigorously as you pour it. Now put the tempered egg yolk mixture back into the remaining milk. Continue to cook for about 10-15 minutes, stirring frequently. Don’t boil the mixture.
Pour the heavy cream into a medium bowl. Place a sieve over the bowl. Transfer the custard mixture into the heavy cream through the sieve and add lemon juice. Whisk the mixture until smooth. Cover with plastic wrap, making sure the plastic touches the custard. Cool completely. The custard can be refrigerated overnight.
Once the custard is cooled, pour it into the prepared ice cream maker and run according to your specific ice cream maker manual.
Transfer into airtight container, and store in the freezer.