Place the beef in the freezer while preparing the other ingredients, about 15 minutes. Once chilled, season both sides of the steak with ½ teaspoon each salt and pepper. Slice the beef into thin strips.
Start warming a large pot of water over high heat to cook the noodles. Once boiling reduce the heat to low and keep warm.
Combine the broth with 2 tablespoons cornstarch. Whisk until blended and set aside.
Heat a large heavy skillet over medium-high heat. Add 1 tablespoon vegetable oil and heat until shimmering. Add half the steak strips to the skillet and brown on one side before turning. Stir and continuing cooking for about 2-3 minutes or until no longer pink. Remove from the skillet to a plate. Repeat adding another tablespoon of oil and the remaining sliced beef. Cover and keep warm.
Add the remaining 1 tablespoon vegetable oil and 1 tablespoon butter to the skillet. Once hot, add the mushrooms in a single layer (as much as possible) and cook, undisturbed, until the mushrooms are dark brown on one side, their liquid has been released and then evaporated. Stir and continue cooking until all the mushrooms are golden brown, about 10 minutes.
Add the sliced shallots to the skillet with the mushrooms and cook, stirring frequently, until softened, about 5 minutes. Add the tomato paste, soy sauce, mustard, Worcestershire sauce and thyme. Cook, stirring constantly, for about 1 minute.
Add the white wine into the skillet and deglaze the bottom scraping up any browned bits. Cook until the wine is reduced to about 1/4 cup.
Whisk the beef broth and cornstarch mixture once more, then add to the skillet along with the cooked beef and any accumulated juices. Reduce the heat to low and cook until the mixture starts to simmer and the gravy thickens, about 5 minutes.
Meanwhile, cook egg noodles in salted water per package directions. Reserve one cup of pasta water and drain the noodles. Keep warm.
Scoop the sour cream into a small bowl or 2 cup measure. While whisking constantly, temper the sour cream by slowly drizzling about ⅔ cup of the reserved hot pasta water into the sour cream. Sour cream can curdle if warmed quickly. Slowly heating, or tempering, assures the sauce won’t break or curdle.
Add the sour cream mixture to the skillet along with the remaining ½ teaspoon of salt and pepper. Heat gently until warmed through. Do not boil! Remove from the heat.
Fold in fresh parsley and check seasoning adding more salt or pepper as needed. Add a little pasta water to the sauce if needed to thin the sauce.
Serve immediately. Spoon over hot noodles in individual bowls or fold the sauce and noodles together in the pan. Serve with fresh crusty Artisan bread.