Cut the round steak into strips and flour them lightly.

Brown the floured steak in a skillet over medium-high heat.

Add the sliced onion to the skillet and sauté until softened.

Dissolve the beef bouillon cubes in hot water.

Pour the bouillon mixture over the meat and onions.

Cover the skillet and simmer for 2 hours, or until the meat is tender.

Add the canned mushrooms to the skillet.

Stir in the sour cream gently.

Heat through, but do not boil.

Serve the beef stroganoff over cooked noodles.