Boil dried mushroom in 4 cups of water for 15 minutes in a covered pot. Strain the boiled mushrooms and dice them; keep the strained mushroom stock in the pot.
Dice onions and carrots, sauté with mushrooms in margarine until onions are light brown and soft.
Boil the millet in 1/2 cup of water for about 5-10 minutes and drain.
Brown the flour in a dry skillet and gradually add warm mushroom stock to make a smooth paste.
To the remaining mushroom stock add the boiled millet and the previously sautéed carrots, onions and mushrooms and cook for 20 minutes.
10 minutes before the soup is done add flour paste and season it with salt and pepper.
Before serving add sour cream.