In a large skillet, heat 1 tablespoon of oil over medium heat. Add the ground beef and cook for 5–7 minutes, breaking it apart with a spatula until browned and no longer pink. Drain any excess fat.

Add 1 diced yellow onion to the skillet. Sauté for 2–3 minutes until the onion becomes translucent and aromatic.

Fold in 8 ounces of sliced mushrooms. Cook for an additional 4–5 minutes, stirring until the mushrooms are softened.

Reduce the heat to low and stir in 1 cup of beef broth and 1 cup of sour cream until fully combined. Simmer for 3–4 minutes.

While the sauce simmers, bring a pot of salted water to a boil. Cook 8 ounces of egg noodles according to package instructions for 8–10 minutes until al dente.

Add the drained noodles to the skillet with the beef and mushroom sauce. Gently toss together over low heat for 1–2 minutes. Serve immediately, garnished with freshly chopped parsley.