Fill a large pot with water and bring to a boil for the noodles.
Brown the beef.
Add the onion and mushrooms and cook till the onions become translucent.
Add sherry, rosemary, nutmeg, salt and pepper.
Simmer covered on low temp, stirring occasionally for 30 minutes or until beef is tender.
Meanwhile, cook noodles according to package directions.
When the noodles are done mix the sour cream into the meat mixture.
Add the noodles. Remove from heat and let stand for 5 minutes, dust with paprika, and serve.
When I was growing up my mom always made Beef Stroganoff with ground beef, because it was cheaper. I was an adult before I found out it wasn't supposed to be that way. I added the sherry, rosemary, nutmeg, and paprika to her recipe. She served it with rice instead of noodles too.