Preheat oven to 375°F. Grease a 9x13-inch baking dish.
Cook noodles in salted water 1–2 minutes under package directions. Drain and set aside.
In a large skillet over medium-high heat, brown ground beef. Drain excess grease if needed.
Add butter, then onion. Cook 2–3 minutes. Add mushrooms and cook 6–8 minutes until browned. Add garlic for 30 seconds.
Sprinkle flour over the mushrooms and stir 1–2 minutes.
Slowly stir in broth. Add Worcestershire, Dijon, paprika, pepper, and a small amount of salt. Simmer 3–5 minutes until thickened.
Reduce heat to low. Stir in sour cream (and cream cheese if using) until smooth. Taste and adjust seasoning.
Stir beef and noodles into the sauce. Spread in the baking dish. Top with cheese if using.
Bake uncovered 20–25 minutes until bubbling.
Optional crunch: toss panko with melted butter and sprinkle on top during the last 10 minutes, or broil 1–2 minutes at the end.
Rest 10 minutes before serving.