In a large pot over medium heat, heat olive oil and sauté diced onions until translucent (3-4 minutes). Add minced garlic and cook until fragrant (1 minute).

Add sliced mushrooms and sauté until browned (5-7 minutes).

Pour in vegetable broth, thyme, salt, and pepper. Bring to a gentle boil then reduce heat to simmer.

Stir in pasta and cook according to package instructions (8-10 minutes).

Once pasta is al dente, stir in heavy cream and adjust seasoning as needed. Simmer for an additional 2 minutes.

Serve hot, garnished with fresh herbs if desired.