Puree the strawberries with the juice of the lime. Season the pulp with sugar and cardamom, stir in the cream.
Soak the gelatine in cold water. Do not squeeze out and melt in a small saucepan. Add some of the strawberry pulp and stir well. Add the mixture to the remaining strawberry pulp and mix everything well. Brush through a fine hair sieve and fill into the isi. Screw in 2 capsules one after the other. It is advisable to hold the isi upside down.
Shake vigorously, foam in dessert glasses and serve.