Slow cooked beans with walnut pesto (TM5)

• 200 g dried navy beans (see Tips)
• water, for soaking

Walnut pesto

• 50 g Parmesan cheese, cut into pieces (3 cm)
• 50 g walnuts
• 30 g fresh flat-leaf parsley, leaves only
• 100 g olive oil
• 1 pinch salt
• 1 pinch ground black pepper

Slow cooked beans

• 20 g olive oil
• 3 garlic cloves, cut into halves
• 200 g brown onion, cut into wedges (1 cm)
• 120 g carrots, cut into pieces (2 cm)
• 60 g celery, cut into pieces (2 cm)
• 200 g water
• 1 tbsp Vegetable stock paste (see Tips)
• 400 g canned chopped tomatoes
• 400 g tomato passata
• 2 tsp dried oregano
• crusty bread, to serve (optional)