In a bowl, whip the heavy cream with powdered sugar until stiff peaks form.

In a separate bowl, mix mascarpone with vanilla extract and optionally, lemon liqueur.

Gently fold the whipped cream into the mascarpone mixture until smooth.

In a shallow dish, combine limoncello with lemon juice and lemon zest.

Quickly dip the ladyfingers into the limoncello mixture and place a layer in a serving dish.

Spread half of the mascarpone cream over the ladyfingers, then add another layer of soaked ladyfingers.

Spread the remaining cream on top and smooth it out.

Refrigerate for at least 4 hours, preferably overnight.

Before serving, garnish with whipped cream and grated lemon zest.