01 -
Combine lemon juice, water, sugar, and lemon zest in a medium saucepan over medium-high heat. Simmer while occasionally stirring until sugar dissolves and mixture reduces slightly, approximately 5 minutes. Remove from heat, strain through a fine-mesh sieve into a shallow bowl, and refrigerate until cooled.
02 -
In a medium saucepan, whisk together egg yolks, whole egg, and sugar until combined. Stir in lemon juice, zest, and salt. Add butter pieces and cook over medium-low heat, stirring continuously, until the mixture thickens, approximately 5-8 minutes. Strain through a fine-mesh sieve into a medium bowl, cover with plastic wrap, and refrigerate until fully cooled.
03 -
Using a stand mixer with a whisk attachment, whip heavy cream to stiff peaks. Transfer whipped cream to a separate bowl. Replace the whisk attachment with a paddle attachment. Beat together mascarpone cheese, sugar, lemon syrup, and vanilla extract on high until well combined. Add 1 cup of whipped cream to the mixture and beat until incorporated, then gently fold in the remaining whipped cream.
04 -
Quickly dip each ladyfinger into the prepared lemon syrup, ensuring they are soaked but not soggy. Arrange in two rows of six along the bottom of an 8-inch square dish. Spread half of the lemon curd evenly over the ladyfingers, followed by half of the mascarpone filling. Repeat with another layer of syrup-soaked ladyfingers, the remaining lemon curd, and half of the remaining mascarpone filling. Pipe the rest of the mascarpone filling on top using a pastry bag or a ziplock bag with the corner cut off. Cover and refrigerate for at least 6 hours before serving.