01 - Wash and zest the lemons, then juice them to yield approximately 4 tablespoons of juice.
02 - In a mixing bowl, whisk eggs and sugar until pale and slightly thickened.
03 - Add lemon zest, lemon juice, vanilla extract, and a pinch of salt to the egg mixture and whisk until combined.
04 - Transfer the mixture to a small saucepan and cook over low heat, stirring constantly, until slightly thickened, about 5 to 7 minutes; do not boil.
05 - Remove from heat and let cool to room temperature.
06 - In a separate bowl, whip the heavy cream until soft peaks form.
07 - Gently fold the cooled lemon mixture into the whipped cream until smooth and homogeneous.
08 - Spoon the mixture into individual serving glasses.
09 - Refrigerate for at least two hours before serving to allow flavors to meld and texture to set.
10 - Optionally garnish with additional lemon zest and fresh mint leaves before serving.