Limoncello cream:
In a saucepan, combine the lemon juice, limoncello, zest, and half of the sugar, and bring to a boil.

In a mixing bowl, whisk the eggs with the remaining sugar.
While whisking, gradually add the hot liquid to warm the eggs.
Return to the saucepan and place over low heat.
At this point, it is necessary to stir constantly with a whisk until the first boil appears.

Remove from heat, transfer to a container with a high rim, and add the cubed butter.
Emulsify the lemon cream with an immersion blender.

When all the butter is added and the cream is smooth, strain through a fine-mesh sieve or cheesecloth, cover with plastic wrap directly on the cream, and refrigerate for at least 8 hours.

Limoncello syrup:
Mix the water and sugar well in a small saucepan. Bring to a boil. Turn off the heat and add the limoncello.

Mascarpone mixture:
With an electric mixer, beat the mascarpone to soften it, then incorporate the limoncello cream and mix well.

Assembly:
Dip the cookies in the limoncello syrup for a few seconds.
Arrange them at the bottom of a dish or individual glasses (if you want individual portions).
Cover with half of the mascarpone cream.
Cover with dipped cookies and finish with the cream.
Garnish with lemon zest and refrigerate until serving.