Cook the egg noodles according to the package instructions. Drain and set aside.

Meanwhile, heat oil in a large skillet over medium-high heat. Add the beef slices and cook until browned, about 3-4 minutes per side. Transfer the beef to a plate and set aside.

In the same skillet, add the chopped onion and cook until softened, 5-8 minutes.

Add the garlic and sliced mushrooms, cooking for an additional 3-4 minutes until the mushrooms are tender. Stir in the beef broth, Worcestershire sauce, and Dijon mustard. Let simmer for about 5 minutes to reduce slightly.

In a small bowl, whisk together the cornstarch and cold water to form a slurry. Stir the slurry into the sauce and cook for another 2 minutes, until the sauce thickens.

Reduce heat to low and stir in the Greek yogurt until the sauce is creamy. Return the beef to the skillet and season with salt and pepper to taste.

Serve the beef stroganoff over the egg noodles. Enjoy!