Syrup
Mascarpone Cream
Garnish
To make the syrup, in a medium saucepan, combine limoncello, water, sugar and lemon juice. Set over medium heat and bring to a simmer, whisking to dissolve the sugar. Once simmering, cook for about 5 minutes, or until it thickens slightly. Set aside in a shallow bowl.
To make the cream, in a large bowl, combine egg yolks and sugar. Beat at medium speed with a handheld mixer for about 2 minutes, or until the mixture has doubled in volume. Add limoncello and lemon zest and whisk until smooth. Add the mascarpone and beat again at medium speed until fully combined, about 1 to 2 minutes.
To assemble, add about 1 cup of the mascarpone mixture to the bottom of a 9 by 13 inch baking pan.
Working with about ½ of the cookies, dip one lady finger at a time into the limoncello syrup briefly on each side until it has softened but can maintain its shape, about 1 to 2 seconds. Place them on top of the mascarpone layer in the baking dish, breaking them as needed to fit the space and make an even layer. Add about half of the remaining mascarpone mixture on top and smooth it into an even layer. Repeat the same process with another layer of lady fingers, followed by the remaining mascarpone cream on top.
Cover and let sit in the fridge for at least 3 hours before serving. Garnish with fresh lemon zest, wheels and a few mint leaves before serving.