Step 1

Liberally season all sides of the steak with salt and pepper. Let steak rest at room temperature for 10-15 minutes.

Step 2

Place a large heavy-bottomed dutch oven over medium heat for 5 minutes to preheat. Add the oil to the pan and heat for 30 seconds. Sear the steak on all sides until a golden-brown crust forms, about 3-5 minutes per side.

Step 3

After searing, remove steak to a sheet tray or wire rack and turn the heat to low. Add half of the wine to the dutch oven and deglaze, scraping up the browned bits from the bottom of the pot and let reduce slightly.

Step 4

Add the butter to the pot and melt over medium heat. Add the onions, a pinch of salt and pepper and cook until they start to soften, then add the mushrooms and cook until most of the moisture has evaporated, about 3-5 minutes. Stir in the garlic and thyme and cook for an additional minute. Remove from the heat.

Step 5

Slice the seared steak against the grain. Depending on how thick it is, it may still be raw inside; this is ok, as it will finish cooking later.

Step 6

Return the pan to medium heat. Add the sliced steak to the onion mixture, along with the flour. Stir while cooking for 2-3 minutes. Add the remaining wine, beef stock, mustard, Worcestershire sauce, and a heavy pinch of salt and pepper. Stir to combine and cook over medium heat until the mixture comes to a simmer, stirring frequently.

Step 7

Once the mixture has come to a simmer, stir in the egg noodles and turn the heat to low. Cover and simmer for 8 minutes. Stir and check the noodles for doneness, covering and cooking an additional 1-2 minutes if needed. Taste for seasoning, adding more salt and pepper if needed.

Step 8

Once the noodles are cooked, gently stir in the sour cream until combined and warmed through.

Step 9

Remove from heat and stir in the fresh parsley or chives and serve.