1 lb. fresh mushrooms, sliced
6 tbsp. butter
1 lg. onion, chopped
6 tbsp. flour
7 c. boiling water
5 c. cubed raw potato (6-7 red potatoes)
3 tsp. salt
3/4 tsp. pepper
4 tsp. Worcestershire sauce
4 tbsp. chopped parsley
2 tbsp. lemon juice
8 oz. sour cream
1 egg yolk

Melt the butter in the soup pan and saute the mushrooms and onions until both are lightly browned.

Measure out the flour and stir into the mushrooms and onions. Cook and stir until the flour is browned. Gradually stir in the boiling water until blended.

Add the potatoes, salt, pepper, Worcestershire sauce, parsley and lemon juice. Bring to a boil then cover, cook and simmer for 30 to 40 minutes or until potatoes are done.

Stir egg yolk into sour cream. Drop spoonfuls of sour cream mixture into soup and stir well after each addition.