Peel the bananas, finely puree with sour cream, 1 tablespoon lemon juice, sugar and vanilla sugar and season to taste. Soak gelatine, melt in a water bath, stir into the banana mixture. Chill for 3-4 hours or overnight.
Cut off eight lobes, arrange on plates with mint leaves. Season the strawberry sauce with lemon juice and pour around the cams.