In a small pan, combine sugar, lemon zest, and lemon juice. Stir and bring to a boil.
Once boiling and the sugar dissolves, remove from heat.
Stir in the Limoncello liqueur and set aside to cool.
Beat the Mascarpone cheese with lemon zest, lemon juice, and Limoncello liqueur until smooth.
Add the lemon curd and mix well.
In a separate bowl, whip the heavy cream with powdered sugar until stiff peaks form.
Gently fold half of the whipped cream into the mascarpone mixture, then fold in the remaining whipped cream until fluffy.
Dip ladyfingers briefly in Limoncello syrup and arrange in the bottom of an 11×8-inch pan.
Spread half of the Limoncello mascarpone mixture over the ladyfingers.
Spread ⅓ cup lemon curd on top of the mascarpone layer.
Repeat with another layer of ladyfingers and mascarpone.
Pipe any remaining mascarpone around the edges if desired.
Optionally, garnish with more whipped cream and lemon zest.
Refrigerate for at least 4 hours before serving to allow the flavors to meld.
