In a medium saucepan, combine freshly squeezed lemon juice, water, and granulated sugar over medium heat and stir until the sugar dissolves.

Remove from heat and let the lemon syrup cool completely.

In a mixing bowl, whip the cold heavy cream with powdered sugar and vanilla extract until soft peaks form.

In another bowl, beat the mascarpone cheese and lemon zest until smooth, then fold in the whipped cream.

Briefly dip each ladyfinger in the lemon syrup and layer half in a 9x9-inch dish.

Spread half of the mascarpone cream mixture over the ladyfingers and repeat with the remaining ingredients.

Cover and refrigerate for at least 4–6 hours or overnight for best results.

Garnish with lemon zest or candied lemon slices before serving.