In a wok or a frying pan heat oil over medium high heat. Add mustard seeds and cumin seeds and let it sizzle. Add onion and sauté it until translucent, 3 to 4 minutes. Add garam masala, dhana-jeeru, green chili, ginger and garlic. Sauté everything for two more minutes. Add tomato paste and sauté for a minute. Add spinach and ½ cup water. Cover the pan and let spinach cook until slightly wilted, 2 to 3 minutes. Season with salt, add kasuri methi and let spinach cook until it is fully cooked, 4 to 5 minutes. Take off the heat.
With a blender or an immersion blender puree the spinach until smooth. Transfer pureed spinach to a wok or a frying pan again and add fried paneer. Let it simmer for 5 minutes covered with a lid.
If fried paneer or cubed paneer is not available, cut paneer into ¾ inch cubes. Heat 3 tablespoons oil in a non-stick pan and sauté paneer until light golden brown, 5 to 7 minutes.
Recipe by Lovely Masala at http://www.lovelymasala.com/palak-paneer/