400 g (13 oz) can kidney beans, drained and rinsed
400 g (13 oz) can black-eyed beans, drained and rinsed
1 tablespoon tomato purée
1 teaspoon paprika (optional)
4 tablespoons finely chopped flat leaf parsley
1 small egg, lightly beaten
100 g (3 1/2 oz) fresh white breadcrumbs
250 ml (8 fl oz) natural yogurt
1 small garlic clove, crushed
2 teaspoons lemon juice
salt and pepper
4 soft flour tortillas, warmed, to serve
lettuce leaves, to garnish
Heat 2 tablespoons of the oil in a small frying pan and cook the onion gently for 6–7 minutes. Add the chopped garlic and cook for a further 2–3 minutes, until really soft and golden.
Meanwhile, place both lots of beans in the large bowl of a food processor with the tomato purée, paprika, if using, and half the parsley. Pulse until the mixture becomes a coarse paste. Tip into a bowl and add the egg, breadcrumbs and cooked onion mixture. Season with salt and pepper, then mix well and shape into 4 large burgers.
Heat the remaining oil in a large nonstick frying pan and fry the burgers gently for 8–10 minutes, turning once, until crisp and golden.
Meanwhile, mix the yogurt with the crushed garlic, the remaining parsley and the lemon juice. Season with salt and pepper and set aside.
Serve the burgers with warmed tortillas and the yogurt and garnish with lettuce leaves.