Simmer the raspberries, sugar, lemon juice, lemon peel, vanilla sugar and the prosecco in a saucepan for approx. 10 minutes. Then brush through a fine sieve so that the seeds of the raspberries remain.
Soak the gelatine in a little cold water according to the instructions on the packet. Then squeeze out, dissolve and stir into the liquid raspberry sauce. Let cool until the mass starts to gel. Beat the whipped cream until stiff, beat the egg white until stiff and gradually stir both into the raspberry sauce. Divide between 6 dessert glasses and chill.
Garnish with a dollop of whipped cream, a raspberry and a mint leaf.