Step 1

Season the meat with 1/8 teaspoon of salt and 1/4 teaspoon of pepper. In a large skillet over medium-high heat, heat 1 tablespoon of oil until shimmering. Add the beef and cook until seared but still pink inside, 1 to 2 minutes per side. Transfer the meat with its juices to a plate.

Step 2

Reduce the heat to medium and add the remaining 2 tablespoons of oil to the skillet. Add the shallot and cook, stirring, until softened, about 1 minute. Add the mushrooms, and garlic, and cook, stirring occasionally, until the mushrooms have released their water and it has evaporated, for 8 to 10 minutes.

Step 3

Sprinkle the mushrooms with the flour and stir until well combined. Add the broth and, stirring, bring to a boil. Reduce the heat to low, add the remaining salt and pepper and cook until the mixture thickens and reduces slightly, about 5 minutes. Stir in the mustard until well incorporated. Add the sour cream, stirring until incorporated. Return the meat and any accumulated juices to the pan and cook until the meat is just warmed through, but still medium-rare, 1 to 2 minutes.

Step 4

Serve warm, garnished with the parsley, over the noodles.