Add sliced mushrooms and cook until tender and browned.
Stir in flour, Dijon mustard, Worcestershire sauce, and vegetable broth; simmer until thickened.
Reduce heat, stir in sour cream, heavy cream, smoked paprika, and peas or spinach; season with salt and pepper. Combine with cooked pasta and garnish with parsley.
Notes
For a vegan version, substitute dairy ingredients with plant-based alternatives and omit Worcestershire sauce.