500 ml(2 cups) extra-virgin olive oil2carrots, diced2celery stalks, diced1onion, diced4thyme sprigsPinchof fennel seeds200 gm(1 cup) each of dried borlotti and cannellini beans, soaked overnight in cold water, drained1 kgpiece of skinless tuna, cut into 3cm pieces200 gmbaby green beansTo serve:lemon wedges
Heat 1 tbsp olive oil in a large flameproof casserole over medium heat. Add carrot, celery, onion, thyme and fennel seeds and sauté over medium heat until vegetables just soften (5-7 minutes). Add drained beans, remaining olive oil and 500ml water and bring to the simmer. Reduce heat to low, cover and cook until beans are just tender (1-1½ hours). Add tuna and green beans and cook until beans are tender and tuna is cooked (4-5 minutes). Season to taste and serve immediately with lemon wedges.