Do not boil the soup, especially if you add soured cream or natural yogurt.
Add the soured cream and cook, stirring, until just warm.
In another bowl mix the remaining soured cream with ketchup and tomatoes.
Beat in the eggs, and then the soured cream until well combined.
Take the pan off the heat and stir in the soured cream.
Mix together the soured cream, yogurt, honey and mint.
However, it can also be made from acidulated or bacteriologically soured cream.
Serve hot with boiled rice and a dollop of soured cream on top, if you wish.
Cover again for a minute or so, then add the soured cream and beat the potatoes well.
Soften the cheese, then beat in the soured cream or fromage frais.