12 large lemons (for ¾ to 1 ½ cups fresh lemon juice)
2 envelopes unflavored gelatin
2 cups sugar
4 1/2 cups water
mint sprigs for garnish (optional)
Zest 3 of the lemons and set the zest aside. Juice all 12 of the lemons. It should yield about 1 1/2 cups lemon juice (I’ve made it several times and a couple times I only yielded ¾ cup juice thanks to smaller lemons and when I only had 8 lemons – still turns out fantastic but the ideal would be to get about 1 ½ cups fresh lemon juice).
In a medium saucepan, combine the gelatin, sugar and water, stirring constantly over medium-low heat, until the gelatin is dissolved, about 5-6 minutes. Remove the pan from the heat and stir in the lemon juice and lemon zest.
Pour the mixture into a glass 9X13-inch pan. Cover the pan and freeze the mixture until it is partially frozen. It will depend on the temperature/conditions of your freezer but mine took about 6 hours (could be anywhere from 3 to 7 hours). Remove the pan from the freezer and whisk the partially frozen mixture, bringing in the more frozen parts form the edges and whisking until everything is smooth but still slushy and cold. Cover and return the pan to the freezer for another 2-3 hours. Again, whisk the mixture until slushy and the more frozen parts are incorporated. Cover and return the pan to the freezer until firm, about 4 hours or overnight.
Remove the lemon ice from the freezer about 20 minutes before serving. Scoop into chilled dessert cups (or not chilled, your choice) and garnish with mint sprigs, if desired.