Mushrooms clean, cut arbitrarily, leek cut into half rings.
Next, following the original recipe, we need to whish mushrooms and onions in a blender. As a result, we need to get evenly chopped (as small as possible) onion-mushroom mass. Since it happened, because in the end you still have to beat the soup in a blender to get the consistency of the cream soup.
Chopped mushrooms and onions then place in a saucepan with boiling sour cream.
Add the broth and season with salt, black pepper, sugar. Sugar quite a bit.
In the original recipe it was recommended "to cook until all the contents become a homogeneous dense mass". Because I have the mushrooms and onions chopped (to put it mildly) not very evenly, the soup could hardly be mass. I cooked for 10 minutes, until cooked onions. You need to try.
On this was supposed to end preparation. But, since I have the mushrooms and onions were badly chopped, the soup had nothing in common with the desired consistency of cream soup - across different-sized pieces of mushrooms and onions.
So I poured the contents of the pot into a blender and whipped.
The result was a cream soup consistency characteristic.
The soup is easy enough since not "weighted" potato, other vegetables, cereals.