Toast the bread, then tear into pieces and put in a food processor with the parsley, lemon zest, ½ tbsp olive oil, a good pinch of salt and pepper and the chilli flakes, if using. Blitz to breadcrumbs. Set aside.

Heat the remaining oil in a pan and add the leeks, carrots, celery and fennel along with a splash of water and a pinch of salt. Cook over a medium heat for 10 mins until soft, then add the garlic and tomato purée. Cook for 1 min more, then add the thyme and white wine. Leave to bubble for a minute, then add the beans. Fill the can halfway with water and pour into the pot.

Bring the cassoulet to the boil, then turn down the heat and leave to simmer for 15 mins before removing the thyme sprigs. Mash half the beans to thicken the stew. Season to taste, then divide between bowls and top with the herby breadcrumbs to serve.