Start by pouring cold heavy cream into a large mixing bowl. Using an electric mixer, whip the cream until medium peaks form (about 3-5 minutes). Set aside.

In another bowl, combine mascarpone cheese, granulated sugar, lemon zest, fresh lemon juice, Limoncello, and vanilla extract. Whisk until smooth and creamy.

Gently fold the whipped cream into the mascarpone mixture in two batches, maintaining a light texture.

Pour milk into a shallow dish. Quickly dip each ladyfinger in the milk for 1-2 seconds. Arrange them in a single layer in an 8x8-inch dish.

Spread half of the creamy mascarpone mixture over the ladyfingers. Repeat with another layer of soaked ladyfingers and the remaining mascarpone mixture.

Cover and refrigerate for at least 4 hours, preferably overnight, to allow flavors to meld.

Dust with powdered sugar and garnish with lemon slices or zest curls before serving. Cut into squares and enjoy!