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 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.