For the cream, mix the sour cream with sugar, lemon zest and limoncello. Beat Cremefine until stiff and fold in carefully. Spread 1 tablespoon of this mixture in a suitable form.
Mix the lemon juice with powdered sugar. Soak the ladyfingers in the liquid and place them in the mold with the sugar facing down. Cover with 3/4 of the raspberries, drizzle some soaking liquid over them if necessary. Layer a layer of cream and another layer of soaked ladyfingers in the mold. Then finish with cream and decorate with the remaining raspberries. Leave to stand for a few hours - preferably overnight - until eaten.