Bring a large pot of heavily salted water to a rolling boil. Add your wide egg noodles and cook according to the package directions until tender but still wavy. Drain, toss with a splash of oil to prevent sticking, and set aside.

Heat olive oil in a large skillet over medium-high heat. Add the ground beef, breaking it into coarse crumbles, and season with salt and pepper. Let the beef sit undisturbed for 3-4 minutes to develop a heavily browned crust, then cook through and remove to a plate.

Lower the heat to medium and melt the butter into the beef drippings. Add the sliced cremini mushrooms and diced onion, cooking until the mushrooms are tender and have slightly darker, caramelized edges.

Add the minced garlic and cook for 30 seconds. Sprinkle the flour over the vegetables, stirring constantly for 1 minute. Slowly whisk in the beef broth, Worcestershire sauce, and Dijon mustard until smooth.

Simmer the liquid for 3-5 minutes until it reduces into a thick, creamy, light brown gravy. Return the browned beef to the skillet to absorb the flavors, then remove completely from the heat.

Off the heat, gently stir in the sour cream until the sauce is velvety and glossy. Place a bed of the cooked egg noodles in a bowl and top with a generous ladle of the beef and mushroom gravy.

Finish with a small dollop of bright white sour cream in the center and scatter vibrant green minced fresh parsley flakes over the top. Serve immediately.