Sensational Beef Stroganoff

1 pound boneless beef top round stead
2 T butter
1/2 cup chopped onion
1 can cream of mushroom soup
1/2 t paprika
1/2 cup sour cream or yogurt
Hot cooked noddles

Slice beef across the grain into thin strips. In 10 inch skillet over high heat, in 1 T of butter cook half of beef and half of onion until meat is no longer pink and onion is tender; set aside Repeat with remaining butter, beef and onion. Return meat mixture to skillet. Stir in soup and 1/2 t paprika heat through, stirring occasionally. Remove fro heat Stir in sour cream. Serve over noodles. Sprinkle with parsley for Garnish.