Blitz the chopped onions in a food processor, then press through a sieve over a bowl to extract the onion juice. Set the juice aside and discard the onion pulp.

Put the coriander, chilli, lemon juice, sesame oil, vinegar, ginger and garlic paste, chaat masala, cumin, turmeric, the onion juice and some seasoning in a food processor. Whizz together to make a marinade.

Tip the chicken into a large bowl along with the marinade, mix to coat and leave for 1 hr, or overnight.

Skewer the chicken pieces onto 4-6 long metal skewers. Cook on the barbecue over ashen coals or wood. Alternatively, cook on a gas barbecue or under a hot grill for 15-20 mins, turning frequently until charred and cooked through.

Serve the skewers with naan (Afghan naan is preferable), the sliced onion and tomatoes, and some Afghan chutney and garlic yogurt (see recipes, below).