Place the stew meat in a medium bowl and season it generously with salt and pepper. Mix to combine.
In a dutch oven, heat 2 tablespoons olive oil over medium-high heat. Once the dutch oven is hot, sear the meat a few minutes on each side until browned. Remove the pieces of meat with a spoon and transfer it to a bowl and set it aside. (You do not have to cook the meat all the way through. It will continue to cook when we add the broth and simmer it.)
Add the remaining olive oil to the dutch oven and saute the onions, mushrooms, and garlic until the onions start to become translucent about 3-5 minutes.
Add the tomato paste and Worcestershire sauce to the pot and stir together to combine.
Return the seared meat back to the pot and pour in the beef broth. Bring it to a boil and simmer covered for 20 minutes, or until the beef is tender.
Add the dried egg noodles and continue to simmer until noodles are al dente, about 5 minutes.
As soon as you start cooking the noodles, combine the sour cream and cornstarch in a large measuring cup and mix together. Add about a cup of the hot broth from the pot and whisk together until there are no clumps of cornstarch.
Stir it into the pot and continue simmering it with the noodles, until the broth begins to thicken. Taste and adjust seasonings as needed.
Garnish with fresh parsley and serve.