Combine 1 tablespoon sugar, lemon juice, and water in a bowl.
Combine mascarpone, egg yolks, and 3 tablespoons sugar in a large bowl; beat with an electric mixer until smooth and creamy.
Beat egg whites in a glass, metal, or ceramic bowl until until stiff peaks form. Lift your beater or whisk straight up: the egg whites will form sharp peaks. Carefully fold under mascarpone cream.
Dip 2/3 of the ladyfingers in the lemon juice mixture. Layer the ladyfingers dipped side up and dry side down in a rectangular serving dish. Add a layer of half of the crushed raspberries, followed by half the mascarpone cream. Add another layer of soaked ladyfingers, followed by raspberries and the rest of the mascarpone. Garnish with whole raspberries.