Season the beef with the salt and pepper.
Bring a large pot of well salted water to a boil.
Add the oil to a pan over medium-high heat. When the oil is shimmering, add the beef in an even layer and fry until browned on one side. Fry the beef until evenly browned and barely cooked through. Transfer the beef to a bowl.
Melt the butter in the same pan and then add the mushrooms. Let the mushrooms brown on one side before tossing them to brown the other side (a total of about 5 minutes).
Turn down the heat to medium low and add the onions, saute, stirring or tossing regularly to ensure even browning.
Add the egg noodles to the boiling water and cook according to the package directions. When the noodles are done, drain and toss with 1 tablespoon of butter or olive oil.
Add the wine and scrape up any browned bits form the bottom of the pan. Turn up the heat and boil the wine until it's mostly evaporated.
Add the beef stock, worcestershire sauce and bay leaf and then return the beef to the pan. Turn down the heat and simmer for about 5 minutes, until the beef is cooked through and tender.
Add the sour cream and flour to the bowl that held the beef and whisk together until smooth.
When the Stroganoff is cooked, use a ladle to spoon a little of the liquid into the sour cream and whisk to combine. Repeat, adding a little stock at a time until the sour cream mixture is very warm.
Pour the sour cream mixture into the pan and stir to combine. The Stroganoff is done when the sauce has thickened.
Serve the Stroganoff on a bed of buttered egg noodles.