Step 1In a large heavy-bottomed saucepan, heat 1 tablespoon oil over medium-high heat until hot. Add the pancetta, onion, carrot, fennel, celery, garlic, thyme, rosemary and basil, and saute until the vegetables are lightly softened and the mixture is aromatic, about 5 minutes.
Step 2Stir in the diced tomatoes and broth, and bring to a boil over high heat. Reduce the heat to a gentle simmer, cover the pan, and cook the soup base until the flavors are married and the vegetables are soft, about 45 minutes. You should have about 1 quart soup base (add additional water if needed to bring the volume to 1 quart). Taste and season with one-half teaspoon salt and one-fourth teaspoon pepper, or as desired.
Step 3When the soup base is almost done, prepare the mushrooms and the rest of the vegetables: In a medium, heavy-bottomed pot, heat the remaining 2 tablespoons oil over medium-high heat until hot. Stir in the mushrooms, zucchini and broccoli rabe until crisp-tender and lightly colored, 6 to 8 minutes.
Step 4Stir in the soup base, the cooked pasta and beans, and the chopped parsley, and cook until the soup is hot. Taste once more and adjust the salt and pepper if desired. This makes about 1 1/2 quarts of soup. Ladle the soup into bowls and garnish each with one-half tablespoon of pesto.