Meanwhile, let’s prepare the paneer kali mirch gravy. Heat 2 tablespoon ghee in a pan. Add sliced onions and cook until slightly caramelized.
Stir in ginger-garlic paste and cook for another 1-2 minutes. Take it off the flame and allow it to cool.
When comfortable to touch, transfer onion mixture to a blender and blend until completely smooth. If needed, you can add a teaspoon of water to create a thinner paste. Set aside.
In a separate pan, heat the remaining 2 tablespoon ghee to the pan. Add whole spices. As they start to crackle pour-in the onion-ginger-garlic paste.
Add green chilies and tomato puree. Sauté until the mixture starts to leave oil.
Stir in the spices. Cook for a minute or so.
Add cashew paste and lemon juice. Mix to combine. Cook until the oil separates.
Return the marinated paneer cubes to the cooking curry. Mix gently.
Add garam masala and crushed black pepper.
Pour in 3/4 cup of water and bring the paneer kali mirch curry to a boil. Adjust water consistency to liking.
Allow the paneer to simmer in the gravy for a few minutes. This way, it will soak up more flavors and become soft.
Serve hot with warm Indian bread and steamed rice.