Heat oil over medium-high heat in a large saute pan which should be large enough to accommodate the mushrooms, wine and beef.
Season beef with salt, pepper, and paprika, and set aside briefly.
To the heated pan, add white onion and garlic and saute until the onion becomes translucent. Add the mushrooms and saute until they give up their juices.
Add the beef strips to the pan, pour red wine, pouring over the meat, and allow the wine to reduce by half. Add beef stock and return to a boil. Cover, reduce heat, and allow meat to braise until it is fork tender, about 25 minutes.
Bring a pot of water to a boil for the noodles.
Using a slotted spoon, remove meat and mushrooms from pan, cover and keep in a warm place. Allow liquids to reduce and thicken with the pan uncovered.
While the beef stock is reducing, boil the egg noodles until al dente.
Remove sauce from heat and whisk in sour cream and horseradish (which will add stroganoff flavor and stabilize the sauce). Return meat and mushrooms to sauce.
Drain egg noodles well and spoon stroganoff over. Garnish with parsley.