Marinate: whisk yogurt, mustard oil, ginger garlic paste, lemon juice, Kashmiri chili, turmeric, garam masala, cumin, coriander, salt, pepper; coat chicken; refrigerate 2–12 hours.
Thread skewers alternating chicken, onion petals, bell pepper; lay diagonally to fit.
Preheat to 400°F (200°C); spray basket; single layer; cook 12–14 minutes total.
Flip at 6–7 minutes; brush with ghee; done at 165°F (74°C) internal.
Dhungar (optional): hot charcoal in metal bowl on platter, drizzle ghee, cover 3–5 minutes with ventilation.
Serve with lemon, chaat masala, cilantro, mint chutney.