In the same wok heat oil and ghee. Add bay leaf, roughly chopped ginger and garlic. Slit the green chilli from the middle and then add it. Sauté till they the rawness goes. Do not brown it.
Now, add sliced onions, some salt and cook till they become translucent. Add cashews and sauté till onions become soft. Do not brown the onions.
Once the onions become soft, switch off the flame. Remove green chilli and bay leaf. Allow onions to cool a little then transfer to a mixer jar. Add a little water and blend to a smooth paste.
Transfer the paste back to the wok. Add 2 tbsps of prepared kali mirch paneer masala and 1/2 tsp of freshly ground black pepper. Mix well. Cook the onion paste for 4 to 5 minutes on low flame.
Now add 1.5 cups of milk in the wok. Swirl some milk in the mixer jar to take out all the onion paste. Bring the milk to simmer then immediately lower the flame. Do not boil the milk on high heat or it will curdle.
Once the gravy starts to thicken, add 1/2 cup of water, salt to taste and cook on low flame till the gravy thickens and coats the back of the spoon.
Now crush kasuri methi between your hands and add it to the gravy along with some more black pepper. Mix well.
Add diced paneer cubes to the gravy and 1 tbsp of prepared masala. Cook on low flame for another 5 minutes. After 3 or 4 minutes, check for salt. Add if required. Cook for another minute after adding salt and switch off the flame.
Cover and let the gravy rest for 10 to 15 minutes before serving. Serve with hot rotis, naan or paranthas.