In a large stockpot over low heat, warm the olive oil. Add the garlic and cook for 1 minute. Add the leeks, cover, and cook, stirring once or twice, for 6 minutes. Add the carrots, parsnip, celery, zucchini, rosemary, and half of the parsley and season with salt and pepper. Turn the heat to medium and cook, stirring, for 5 minutes. The vegetables should be just beginning to turn gold. Add the tomato paste, stir to coat the vegetables, and cook another 2 minutes. Add the tomatoes, Parmesan rind (if using), beans, and potatoes (if using) and stir well. Turn the heat to high, add the stock, and bring to a boil. Turn the heat to low, add the red chili flakes, and simmer, partially covered, for 15 minutes. Taste and adjust the seasoning, adding more salt and pepper if needed. If the soup is not as flavorful as you like, remove the lid and simmer it over medium heat for another 10 minutes.

Add the pasta to the soup and simmer for 10 minutes more, or until the pasta is al dente, or just barely tender. (Remember you will be reheating the soup, so you want to slightly undercook the pasta. Cooking the pasta directly in the soup will work only if you’re using a very small shape. If using orzo or a larger shape, boil separately for about 7 minutes, drain, and then add to the soup–personally I left the cooked pasta on the side and allowed each person to stir a couple spoonfuls into their bowl of soup so the pasta wouldn’t get mushy. Even for the leftover soup I left the pasta separate and then reheated and stirred in the pasta into each portion). Remove the rind from the soup.

Ladle the soup into mugs or bowls. Top with the remaining parsley and some grated cheese before serving.