Wash, clean and cut the rhubarb into pieces. Simmer rhubarb, sugar and 300 ml water for about 10 minutes
Soak gelatine in cold water. Add tea bags and 2 flowers to the brew, let it steep for 5-7 minutes, then remove tea bags. Squeeze the gelatine and dissolve in warm rhubarb syrup. Pass the brew through a sieve after another 20 minutes
Halve the lemon, squeeze the juice and pour it into the rhubarb syrup. Beat the egg whites briefly and add to the lukewarm syrup. Freeze the sorbet mixture in an ice-cream maker (or put it in a flat, freezable mould and freeze for 3-4 hours, stirring frequently). Arrange the sorbet in bowls and decorate with petals
Waiting time approx. 30 minutes