In a medium saucepan, combine 1 cup of fresh lemon juice and ¾ cup of granulated sugar over medium heat. Stir until the sugar dissolves, about 3-5 minutes. Remove from heat and stir in ½ cup of limoncello and zest from 2 lemons. Allow to cool.

In a large bowl, blend 16 ounces of room-temperature mascarpone cheese until smooth. In a separate bowl, whip 1 cup of heavy cream with ¾ cup of powdered sugar and 1 teaspoon of vanilla extract until soft peaks form. Fold whipped cream into mascarpone, then add 2 tablespoons of limoncello and a pinch of salt.

Dip ladyfingers into the cooled lemon syrup for 1-2 seconds per side and lay them in a rectangular dish. Spread half of the mascarpone cream over the ladyfingers, then repeat with another layer of dipped ladyfingers and the remaining cream.

Cover and refrigerate for at least 4 hours, or overnight, to allow flavors to meld and for a firmer texture.

Uncover the tiramisu, garnish with fresh lemon zest, thin lemon slices, and mint leaves. Slice and enjoy!