Heat oil and butter in a pan.
Add chopped onion and sauté until soft and lightly golden.
Add nigella seeds, mustard seeds, cumin seeds, whole red chilies, garlic, and ginger. Sauté until aromatic.
Add chicken mince and cook on high heat for 3 minutes, breaking lumps.
Add salt, red chili powder, black pepper, coriander powder, and cumin powder. Mix well.
Add sliced tomatoes and yogurt. Mix, cover, and cook on medium flame for 5 minutes.
Remove the lid and cook for another 5 minutes until oil separates.
Add chopped coriander and fried green chilies.
Give coal smoke (dum) for authentic achari flavor.
Serve hot with roti or paratha.