Mushroom Soup

1/2 pound fresh mushrooms
1/2 onion, chopped
1 stick (1/2 cup) butter
2 cans chicken broth
1 container sour cream

Blend mushrooms with small amount of water in blender. Saute onion in butter. Add chicken broth and mushrooms and heat. Stir in sour cream just before serving.

Serves 4.