In a casserole heat the olive oil. Add the onions and cook until golden, about 5 to 7 minutes. Then add the carrots and celery and cook over low heat, stirring occasionally, for 5 minutes. Add the beans, bay leaf and thyme and toss for 1 minute. Then add the beef stock, Parmesan rind (if using), plum tomatoes and their juice, and salt and pepper to taste. (Careful with the amount of salt since Parmesan rind will add a salty flavor.) Bring to a boil, reduce heat and simmer for 1 hour. Add the potatoes, zucchini and savoy cabbage and cook for 20 minutes more or until the vegetables are tender. Finally, add your pasta and cook, covered, for about 10 minutes. Season to taste with salt and pepper, ladle into bowls and serve with some pesto.