Ribollita Soup with large toasted croutons

Ingredients

• 1/4 cup olive oil, plus extra for drizzling
• 2 leeks, white and pale green parts only, cut into 1 cm rounds
• 2 garlic cloves, finely chopped
• 1 stalk celery, finely chopped
• 2 small-medium carrots, finely chopped
• 1/2 tsp freshly ground black pepper
• 1 parmesan rind (if you have it handy!)
• 1 tsp sea salt
• 2 cups tinned cannellini beans, drained and rinsed
• 1 litre chicken stock (or water if you prefer)
• 2 cups kale leaves, roughly chopped, stems removed