¼ iceberg lettuce, trimmed and shredded
½ small lemon, finely grated zest only
800g/1lb 12oz large potatoes, each cut into 8 wedges
1 spring onion, trimmed and finely sliced (optional)
2 spring onions, trimmed and finely sliced
400g tin red kidney beans, drained
20²µ/¾´Ç³ú plain flour
salt and ground black pepper
1 tsp ground cumin
½ tsp paprika (optional)
¼ tsp fine salt
2 tbsp vegetable oil, plus 2 tsp
150ml/¼ pint soured cream or crème fraîche
4 seeded burger buns, split