Combine the lemon juice, water, granulated sugar, and lemon zest in a small saucepan.

Heat over medium heat, stirring until the sugar dissolves.

Simmer gently for approximately 2 minutes, then remove from the heat and cool completely.

Place the mascarpone in a large bowl and mix briefly until smooth.

In a separate cold bowl, whip the heavy cream, powdered sugar, and vanilla until medium-stiff peaks form.

Gently fold the whipped cream into the mascarpone in several additions.

Fold in the fresh lemon zest.

Pour the cooled lemon syrup into a shallow dish.

Quickly dip each ladyfinger into the syrup for approximately 1 second per side.

Arrange one layer of dipped ladyfingers across the bottom of an 8 × 8-inch dish.

Spread half of the mascarpone cream over the ladyfingers.

Spoon a thin layer of lemon curd over the mascarpone.

Add another layer of quickly dipped ladyfingers.

Spread the remaining mascarpone cream over the top.

Cover and refrigerate for at least 6 hours, preferably overnight.

Before serving, garnish with fresh lemon zest and optional thin lemon curls.

Slice into squares and serve chilled.