- Peel the sweet potato and cut into chunks, then steam for about 10 minutes until tender and soft.
- Meanwhile, trim the green beans and scallions and finely chop.
- Drain and rinse the chickpeas and dry well on kitchen paper. Then place in a large bowl and mash with a potato masher.
- Once the sweet potato is ready, add it to the chickpeas and mash again until smooth and combined.
- Mix in the curry paste and coriander with the green beans and scallions, then mix in the egg and flour. Season lightly with salt and pepper and then shape into 4 patties with your hands.
- Heat the oil in a large non-stick frying pan over a medium heat and add the patties. Cook for 5-6 minutes on each side until lightly golden, carefully turning them once with a spatula.
- Toast the pitta bread in a toaster or under the grill. Cut into 4 triangles and arrange on plates with the little Gem lettuce that has been trimmed and separate into leaves. Cut the cherry tomatoes in half and scatter on top.
- Stir the mint into the yoghurt and drizzle on top of the lettuce and add the cooked curried chickpea and sweet potato burgers to the plate. Garnish with the lime.