Finely chop 2 onions and cut 1 onion into large square petals.
Melt butter in a pan, sauté onion petals for 2 minutes until tender-crisp; remove and set aside.
Sauté finely chopped onions, ginger paste, and garlic paste until golden brown.
Add chopped tomatoes, red chili powder, turmeric powder, salt, and chicken pieces; cook on high for 6 minutes.
Add water, cover and simmer for 20 minutes until chicken is tender; fold in onion petals, garam masala, and kasuri methi.