Grind ginger, garlic and green chillies to a fine paste. Heat oil in a kadai and deep fry onions till golden brown.
Drain and place on absorbent paper and cool. Grind the fried onions with two tablespoons of water to a smooth paste.
Preheat oven to 180°C. Heat pure ghee in a narrow mouthed handi, add bay leaves, cinnamon, green cardamoms and cloves.
Stir-fry briefly. Add ginger-garlic-green chilli paste and sauté on high heat for half a minute.
Add the brown onion paste, whisked yogurt, coriander powder, cumin powder and salt to taste. Stir well, add one cup of water and cook on high heat, stirring frequently, till the gravy starts boiling.
Add paneer pieces, chopped coriander and mint leaves. Stir in the fresh cream and crushed black peppercorns.
Sprinkle garam masala powder. Cover the handi with a tight-fitting lid and seal using whole-wheat dough (atta) or alternatively, seal tightly with aluminum foil.
Place sealed handi in the preheated oven and cook for ten to fifteen minutes. Open the handi just before serving and serve immediately.