Saute mushrooms and onion in butter until browned and tender, remove from skillet. Cook meat until light brown (2 or 3 minutes). Reserving 1/3 cup of the broth, stir in remaining broth, ketchup, garlic, and salt. Cover and simmer 15 minutes.

Blend reserved broth and flour; stir into meat mixture. Add sauted mushrooms and onion. Heat to boiling, stirring constantly. Boil and stir 1 minute. Reduce heat. Stir in sour cream; heat.

Serve over hot rice or noodles.