Classic Minestrone Soup (Made easy)

• 2 brown onion
• 1 bunch of parsley, flat leaf
• 0.5 bunch celery, roughly chopped
• 2 carrots, roughly chopped
• 1 zucchini, roughly chopped
• 400 g diced tomato, tinned
• 400 g Cannellini beans, tinned, drained
• 700 g passata (tomato cooking sauce)
• 1 l vegetable stock
• 300 g pasta shells
• 60 g Parmesan cheese to serve (optional)