Beef Stroganoff

1 1/2 pounds beef tenderloin
2 Tbps Butter
1 1/2 beef broth
2 Tbsp ketchup
1 Tsp salt
1 clove garlic
8 ounces fresh mushrooms
1 onion chopped
3 Tbsp flour
1 cup sour cream

Cut meat against the grain in strips about 1 1/2 inches by 1/2 inch. Cook beef and onion in butter and reserve 1/3 cup of the beef broth. Add ketchup, salt, garlic, and cook till meat is tender- about 15 minutes or so. Stir in mushrooms and simmer five minutes. Stir together flour and reserved broth in a plastic container that has a lid so there are no lumps. Add to meat and cook one minute until it thickens. Stir in sour cream and heat through. Serve over egg noodles or rice