Heat the oil in a large deep pot or Dutch oven over medium-high heat. Add the ground beef and ¼ teaspoon of the salt. Cook for 5-6 minutes, breaking it into crumbles, until well browned. Drain any excess fat and transfer the beef to a plate.

Return the pot to medium heat and add the butter. Once melted, add the onion, mushrooms and ¼ teaspoon of salt. Cook for 5-6 minutes, stirring occasionally, until the onion is softened and the mushrooms are golden and have released their liquid. Add the garlic and cook for 1 minute until fragrant.

Sprinkle the flour over the vegetables and stir to coat evenly. Cook for 1 minute, stirring constantly, until the flour smells slightly nutty.

Pour in the beef broth gradually, stirring constantly to prevent lumps. Add the 1 tablespoon of the Worcestershire sauce, Dijon mustard, ½ teaspoon of salt, and black pepper and stir to combine. Return the beef to the skillet.

Add the dry egg noodles to the skillet and stir to submerge. Bring to a boil, then reduce to a steady simmer. Cover and cook for 8-10 minutes, stirring every couple of minutes, until the noodles are tender and have absorbed most of the liquid.

Remove from heat. Let the stroganoff sit for 2 minutes to cool slightly, then stir in 1 tablespoon of Worcestershire sauce and the sour cream until smooth and creamy. Stir in the parsley, then taste for seasoning and adjust with salt and pepper as needed.