01 - Combine water, granulated sugar, lemon juice, and zest in a small saucepan. Heat over medium heat, stirring continuously until sugar completely dissolves. Remove from heat and allow to cool completely before using.
02 - In a chilled mixing bowl, beat heavy cream and powdered sugar with electric mixer until stiff peaks form. Set aside.
03 - In separate bowl, gently beat mascarpone cheese, vanilla extract, and lemon zest until smooth and creamy.
04 - Fold whipped cream into mascarpone mixture gradually until fully incorporated and fluffy. Avoid overmixing to maintain light texture.
05 - Working quickly, dip each ladyfinger into cooled lemon syrup for just 1-2 seconds per side. Cookies should be moistened but not soggy or falling apart.
06 - Arrange half of dipped ladyfingers in single layer in 9x9-inch dish. Spread half of mascarpone cream evenly over cookies using spatula.
07 - Repeat with remaining ladyfingers and mascarpone cream. Smooth top surface with spatula for even presentation.
08 - Cover dish tightly with plastic wrap and refrigerate minimum 4 hours, preferably overnight, to allow flavors to meld and texture to set properly.
09 - Before serving, decorate with fresh lemon slices and additional lemon zest if desired. Serve chilled.