Heat the oil in a large pot over medium heat. Add the onion, carrots, and celery. Add the garlic, salt, and pepper and saute until all the vegetables are tender, 6 to 8 minutes. Add the tomatoes with their juices. Simmer until the juices evaporate, stirring occasionally, about 8 minutes. Add the lentils and stir. Add the broth and stir. Add the thyme sprigs. Bring to a boil over high heat. Cover and simmer over low heat until the lentils are almost tender, about 30 minutes.
Stir in the pasta. Simmer until the pasta is tender but still al dente, about 7-8 minutes. Season with salt and pepper, to taste. Sprinkle with the Parmesan.
There are several variations i use in the recipe.
you can leave out the pasta.
You can add some italian sausage.
use tomato paste instead of diced tomatoes.
you could add some small diced potatoes.