Bring a pot of salted water to a boil. This will be used to cook the pappardelle.
In a deep frying pan, heat up two ounces of olive oil over a medium flame. Add in the sliced sirloin and fry for about six minutes, making sure to continuously stir the meat to cook evenly. Remove the beef from the pan and set aside.
In the same frying pan, warm up two ounces of olive oil over a medium flame. Add in the mushrooms and fry for about two minutes, continuously stirring.
Add in the onion and garlic and fry cook for about three minutes. At this point the mushrooms will have released a lot of their water. Add in the flour and mix together to thicken up mix. Once completely mixed in, add one tablespoon of butter and mix until melted down.
Pour in the white wine and beef stock and bring to a simmer over medium low heat. Once it starts to boil, add in the beef that was set aside. Mix to evenly coat the beef slices. At this point, add salt and black pepper to taste. Cover the pan and continue to cook over a low flame for about ten minutes. After ten minutes of cooking the beef, stir in the sour cream.
While the beef is cooking, the pot of water should already be boiling. Add in the pappardelle and cook for about two minutes less than the package instructions (al dente). Strain and add directly into the pan.
Add in one tablespoon of butter and mix the Beef Stroganoff with Pappardelle together for about three minutes over a medium/low flame.
Remove from the stove and serve with a dollop of sour cream and a sprinkle of freshly chopped parsley. Enjoy, salute and cin cin!