A pungent, tangy North Indian specialty infused with robust pickling spices, mustard seeds, fenugreek, nigella seeds, and fresh green chillies.
Dry-roast the fennel, nigella, fenugreek, and mustard seeds until fragrant, then coarsely crush.
Mix the chicken with yogurt, ginger-garlic paste, crushed spices, turmeric, and 1 tbsp mustard oil; rest for 1 hour.
Thread the chicken cubes onto skewers, leaving small gaps.
Cook over a hot charcoal grill or grill pan, turning and basting with the remaining mustard oil, until charred at the edges and cooked through.
Slide off the skewers and serve hot with onion rings and lemon wedges.