Bring a large pot of salted water to a boil and cook egg noodles until al dente, then drain and set aside.

Heat olive oil in a large skillet over medium-high heat.

Sear the sliced prime rib briefly on both sides until warmed through, then remove and set aside.

In the same skillet, sauté the diced onion until soft and translucent.

Add minced garlic and cook until fragrant.

Add sliced mushrooms and cook until golden and tender.

Stir in Dijon mustard, paprika, salt, and black pepper.

Pour in beef broth and simmer, scraping up any browned bits.

Mix cornstarch with a little water and stir into the sauce with the heavy cream.

Simmer until the sauce thickens and becomes creamy.

Return the prime rib to the skillet and add cooked noodles.

Toss gently until everything is well coated in the sauce.

Garnish with fresh parsley and serve warm.