Superb Squash Soup with the Best Parmesan Croutons

Name: Superb Squash Soup with the Best Parmesan Croutons
Ingredients: Olive oil; 16 fresh sage leaves; 2 red onions, peeled and chopped; 2 sticks celery, trimmed and chopped; 2 carrots, peeled and chopped; 4 cloves garlic, peeled and chopped; 2 sprigs fresh rosemary, leaves picked; 1/2 fresh red chile, to taste, seeded and finely chopped; Sea salt and freshly ground black pepper; 4 1/4 pounds butternut squash, onion squash, or musque de Provence, halved, deseeded and cut into chunks; 2 quarts good-quality Chicken or vegetable stock; Extra-virgin olive oil; 16 slices ciabatta bread; 1 chunk Parmesan, for grating