For the lemon cream on raspberry sauce, soak the gelatin in cold water. In the meantime, mix yogurt and lemon zest. Season to taste with a few drops of sweetener.
Squeeze the gelatine, dissolve and stir into the lemon yogurt. Allow the cream to become semi-solid in the refrigerator. Whip the cream until stiff and fold in with a whisk.
Place the cream in a small bowl and chill for 1-2 hours. Defrost the raspberries and pass through a sieve to remove the seeds. Season to taste with lemon juice and sweetener.
Place raspberry puree in a dessert bowl. Dip a tablespoon briefly in hot water. Form dumplings from the lemon cream and arrange on top of the raspberry cream. Serve the lemon cream on raspberry sauce immediately.