Heat the oil: Heat ghee or oil in a large karahi or deep pan over medium heat. Add the sliced onions and sauté until golden brown and soft, about 5-7 minutes.

1. Cook the ginger and garlic: Add the minced ginger and garlic to the pan. Sauté for another 1-2 minutes until fragrant.
2. Add the chicken: Add the chicken pieces to the pan and brown them on all sides for about 5-7 minutes to lock in flavors.
3. Add the tomatoes and spices: Stir in the chopped tomatoes, ground cumin, coriander, red chili powder, turmeric powder, and salt. Cook for 5 minutes until the tomatoes release their juices.
4. Add the yogurt: Lower the heat and add yogurt to the pan, stirring gently. Cook for another 5 minutes to blend the yogurt into the sauce.
5. Simmer the chicken: Add green chilies and about 1/2 cup of water to the pan. Stir, cover, and let simmer for 20-25 minutes until the chicken is fully cooked and tender. Add more water if the sauce thickens too much.
6. Finish with garam masala: Once the chicken is cooked, sprinkle garam masala and, if using, fenugreek leaves. Stir well to combine.
7. Garnish and serve: Garnish with fresh cilantro and ginger slices. Serve hot with naan, paratha, or steamed rice.