Similar to ribollita (the “reboiled” Italian soup of vegetables and bread), this recipe is a perfect vehicle for putting a wide variety of farm-fresh vegetables to good use. Day-old bread, which functions as a thickener, gives the stew a homey, comforting finish. Use a good quality olive oil–it tastes great drizzled over the completed stew.
In Dutch oven or deep sauté pan, heat 1 tablespoon oil over medium heat. Add leeks and cook, stirring often, until softened but not browned, 1 1/2 to 2 minutes. Add celery, carrots, garlic, rosemary and pepper flakes and cook, stirring, 1 minute. Add broth and cranberry beans; bring to a simmer. Reduce heat to medium-low, cover and simmer 15 minutes.
Add green beans, cover and simmer 5 minutes. Stir in tomatoes, chard and zucchini and return to a simmer. Cover and simmer until vegetables are tender, 6 to 10 minutes.
Remove from heat; season with salt and freshly ground pepper to taste. Add bread and stir to moisten. Cover Dutch oven and let stand until bread has softened and stew has thickened, about 5 minutes. Spoon stew into shallow soup bowls and drizzle some remaining oil over each serving. Garnish with Parmesan shavings if desired and serve immediately.