Heat the butter/ghee in a Kadai on the medium flame. When the ghee is hot enough add cumin seeds.
When the cumin seeds start splatting add bay leaf and whole spices. Saute them until they turn aromatic. Don't burn them.
After that add green chilis and saute them along with spices.
Add onion paste to the spices and mix well. Saute the onion paste until the raw flavor is gone. Stir occasionally, or else this onion paste might stick to the bottom.
Then add ginger garlic paste and saute it until the raw flavor is gone.
After that add the fine paste of cashew, almonds and poppy seeds. Then mix it with the onion paste.
Allow it to cook by closing the lid. stir the mixture in between. So that it won't strick to the bottom.
Then add salt to the cashew paste when the oil gets separated from the mixture. After that add yogurt to the mixture.
Stir well so that the yogurt can mix well with the masala. Cover the lid and allow it to cook.
When the masala is cooked add paneer cubes and mix well with the masala. So that all the paneer can cover with the masala mixture.
Cook it for few mins and stir in between. Then add milk to the kadai and mix well so that the milk properly mix with the masala and makes a thick gravy.
Now close the lid and allow it to cook until it properly cooked.
Then add pepper powder to the gravy and stir well. Allow it to cook until it properly cooked.
Finally, add Kasturi methi to the Nawab paneer gravy and mix well and turn off the stove.
Serve the hot Nawab paneer curry with roti, pulka, naan or butter naan.