. Make the Lemon Curd

1. In a medium saucepan, whisk lemon juice, zest, sugar, and eggs over medium heat.
2. Stir constantly until the mixture thickens (7-9 minutes).
3. Remove from heat, add butter, and mix until smooth.
4. Transfer to a bowl, cover with plastic wrap pressed to the surface, and chill.

2. Prepare the Lemon Syrup

1. In a small saucepan, combine lemon juice, water, and sugar.
2. Heat over medium heat, stirring until the sugar dissolves.
3. Cool and set aside.

3. Make the Mascarpone Cream

1. Beat mascarpone cheese, powdered sugar, and vanilla extract until smooth.
2. In a separate bowl, whip heavy cream to soft peaks.
3. Gently fold the whipped cream into the mascarpone mixture and add lemon zest.

4. Assemble the Tiramisu

1. Quickly dip ladyfingers in lemon syrup and arrange in a 9×9-inch baking dish.
2. Spread half of the mascarpone cream over the ladyfingers.
3. Add a layer of lemon curd.
4. Repeat with another layer of dipped ladyfingers, mascarpone cream, and lemon curd.

5. Chill and Serve

1. Cover and refrigerate for at least 4 hours or overnight.
2. Before serving, dust with powdered sugar and garnish with lemon slices and zest.