Cook noodles in salted water according to package instructions, undercooking slightly to finish with the sauce.

Heat a large nonstick skillet over medium-high heat.

Melt butter over medium heat, add onions, cook for 2-3 minutes. Stir in flour for 30 seconds.

Gradually add broth, Worcestershire sauce, and tomato paste, stirring constantly.

Add mushrooms, thyme, salt, and pepper; cook for 4-5 minutes until thickened and bubbling.

Pour in wine or sherry; boil, then reduce heat and simmer for 4 minutes. Remove from heat.

Stir in sour cream, add cooked noodles, toss to combine, and garnish with parsley.