olive oil, for cooking

1 onion, chopped

1-2 celery stalks, chopped (with leaves, if there are any)

1-2 carrots, chopped

1-2 garlic cloves, crushed

salt and pepper

3-4 cups (a 1 L carton works well) chicken or veg stock

1 14 oz (398 mL) can diced or whole plum tomatoes, with their juice

2 cups canned or cooked navy or white kidney (cannellini) beans (one 19 oz/540 mL can)

1 thin-skinned potato, diced (optional)

a couple sprigs of rosemary and/or thyme

1 small bunch (or a few large leaves) kale, thinly sliced (discard the stems)

thick, crusty day-old bread

grated Parmesan, aged Gouda or cheddar