Mix the sour cream with the plain yoghurt and sugar. Soak the gelatine in a little cold water according to the instructions on the packet. Then squeeze out and dissolve (e.g. in the microwave, but do not boil!). Mix about 3 tablespoons of the sour cream with the gelatine, then stir the gelatine completely into the cream. Whip the cream until stiff and fold in. Chill in the refrigerator.
For the sauce, clean the strawberries (defrost frozen ones first) and puree them with the ingredients listed below. Pour over the cream and serve.
Tip: As an alternative to the strawberry sauce, you can also beat 400 ml passion fruit juice with 2 packets of vanilla sauce (without boiling) in a tall blender for about 3 minutes on the highest setting. Tastes very good too.