In a small saucepan, combine the sugar and water. Bring to a boil over medium heat. Stir until the sugar is melted.
Add in the limoncello and lemon juice and set to the side to cool while making the rest of the tiramisu items.
Tiramisu
In the bowl of a stand mixer, add the mascarpone cheese. Mix for about 30 seconds to loosen up the cheese. Add in the lemon curd and mix just until combined
Add in the limoncello and lemon juice. Mix on low speed just until combined. Do not over mix the mascarpone mixture as it will separate. Set aside.
In another bowl, add in the heavy whipping cream and sugar. Mix on medium-high speed for 2-3 minutes or until stiff peaks form.
Add about half of the whipped cream to the mascarpone mixture and fold it in by hand. Add in the remaining whipped cream and fold in by hand until completely combined.
Prepare your work space-have the ladyfinger cookies unwrapped, the cooled syrup handy and the mascarpone mixture.
Using a 9x13 baking dish with sides, quickly dip a ladyfinger cookie in the syrup, quickly flipping it to coat both sides and laying it flat in the baking dish. Continue until the lady fingers cover the bottom of the dish-cutting some cookies to fit. Soaking too long in the syrup will lead to soggy and mushy tiramisu.
Pour about half of the mascarpone filling over the cookies and spread evenly to the edges.
Repeat with another layer of dipped cookies.
Repeat with another layer of the remaining mascarpone filling.
Cover loosely with plastic wrap and chill for a minimum of four hours, if not overnight.
Whipped Topping
In the bowl of a stand mixer, combine the heavy cream and powdered sugar. Whip to stiff peaks.
Transfer the whipped cream to a piping bag fitted with a large round tip and pipe small dollops across the entire top of the tiramisu.
Sprinkle with the lemon zest.
Notes
This Recipe Can be Doubled: This is a great recipe for a crowd. Simply increase the ingredients proportionately and split it into two dishes.
Make Individual Servings: Make individual servings in little bowls or ramekins.
Lemon Curd: Use store bought or fresh lemon curd.
Toppings: Add fresh fruit like raspberries or blueberries or extra lemon curd.