1In a bowl, add chicken cubes, vinegar, yogurt, ginger-garlic paste, powdered spices, cumin powder, kasoori methi, corn flour, and salt. Mix well and set aside for 30 minutes.
2In another bowl, add sliced onions, tomatoes, green chilies, garlic, powdered spices, cumin seeds, kasoori methi, vinegar and salt. Massage well and marinate for at least 1 hour.
3Heat mustard oil in a kadai until it smokes. Add marinated chicken and fry until crispy and golden brown. Remove and set aside.
4Remove 80% of the oil from the kadai, keeping some for stir-frying. Add marinated onion-tomato mix and cook on high flame until oil separates but onions remain crunchy.
5Add fried chicken to the kadai, toss well, and garnish with fresh coriander. Serve hot with naan or paratha.