Preheat a 4 quart soup pot over medium heat. Saute onion and celery in the oil with a pinch of salt until soft, about 5 minutes. Add garlic and cook until fragrant, 30 seconds or so.
Add mushrooms, salt, pepper and thyme and saute until mushrooms are soft and golden, about 5 minutes.
Add carrots, vegetable broth and lentils. Cover and bring to a boil. Once boiling, lower heat to a simmer and cook until lentils are tender, about 20 minutes depending on your lentils.
Turn heat up to a low boil, add pasta and let cook for about 10 minutes or until pasta is done. Turn off heat and let sit for 10 minutes. Taste for salt and pepper and serve.