Italian Bean Soup
["1/4 lb. cooked ham, in one piece", "2 medium-size celery stalks", "2 medium-size carrots", "1 medium-size onion", "1 medium-size zucchini (about 8 oz.)", "2 (15 to 19 oz.) cans white kidney beans (cannellini), rinsed and drained", "1 Tbsp. olive or salad oil", "1/2 tsp. dried basil leaves", "1/4 tsp. pepper", "1 (14 1/2 to 16 oz.) can stewed tomatoes", "1 (13 to 14 oz.) can chicken broth", "1/2 medium-size bunch spinach, chopped with tough stems removed (about 1 c. packed)", "grated Parmesan cheese (optional)"]
["About 45 minutes before serving:", "Cut ham into 1/2-inch pieces; dice celery, thinly slice carrots, chop onion and dice zucchini. Remove 1 1/2 cups white kidney beans to medium bowl.", "With potato masher or fork, mash beans until smooth."]
["ham", "celery", "carrots", "onion", "zucchini", "white kidney beans", "olive", "basil", "pepper", "tomatoes", "chicken broth", "spinach", "Parmesan cheese"]