Cook egg noodles in boiling salted water until al dente (soft but still a bite); toss with butter once cooked (about 2 tablespoons), and set aside.

In a large skillet, heat oil and add the beef in batches, so that the meat doesn't overcrowd and boil. The beef will cook very quickly. Cook for about 2 minutes per side, depending how thinly you sliced your steak. Remove to a plate and set aside.

Add in the onion and cook until translucent, about 5 minutes.

Add in the mushrooms and cook until soft, another 5 minutes.

Sprinkle in the flour and stir for 1 minute.

Stir in the beef broth and tomato paste and stir until the sauce thickens a little, about 2 minutes.

Return the beef, and all its juice, to the pan.

Add in the sherry, salt, pepper, and thyme.

Reduce the heat and allow the sauce to simmer for about 5 minutes.

Remove the pan from the heat and add in the sour cream.

Sprinkle chopped parsley into the sauce, reserving some for garnish.

Serve over buttered egg noodles.

Enjoy!