Step 1

Cook penne according to package directions. Set aside.

Step 2

In a medium skillet, heat olive oil over medium heat. Add in sliced mushrooms and onions and let simmer until tender, stirring occasionally, about 5 minutes. Season with garlic, thyme, salt, and pepper and stir to incorporate. Sprinkle flour over mixture and stir until no flour is left visible.

Step 3

Stir in vegetable stock, vegetarian Worcestershire sauce, and Dijon mustard. Let sauce simmer until thickened, about 5 minutes.

Step 4

Stir in sour cream and toss with pasta. Top with chopped parsley and shredded Parmesan. Serve warm!