To make your own paneer all you need is Whole Milk, lemon juice and cheesecloth. Check out the recipe with gorgeous pictures here.
Place ghee in large heavy pan over medium high heat. Add cumin seeds and let them sputter. Add the onions and green chilis (if using) and saute until light brown.
Add ginger-garlic paste and saute for 3 minutes more. Add red chili powder and ground coriander and mix well. Add the tomato puree and let it cook for 5 more minutes. Add the spinach and let it cook for another 5 minutes. Add the fried paneer cubes and stir. Cook covered on low for 3 minutes. Add water to achieve desired consistency and salt to taste, simmer another 10 minutes. Add garam masala and mix well.
Serve hot with Indian bread and Basmati rice.