Cut meat across the grain into 2 cm slices, then into strips 3x 1 cm. Melt quarter cup butter in a large skiller. Cook and stir mushrooms inbutter about 5 minutes, remove mushrooms.
In same skillet, brown meat. Reserving two third cup of broth, stir in remainingbroth, the onion, catsup and garlic salt. Cover and simmer 15 minutes.
Blend reserved broth and the flour; stir into meat. Add mushrooms; heat toboiling, stirring constantly. Boil and stir 1 minute. Stir in sour cream,heat through.
Cook noodles as directed on package; drain. Toss with 3 tbs. butter. Servewith stroganoff.