Pan fry the paneer cubes (about 1" cubes) using as little oil or ghee as possible. In my Scanpans I can do this without any oil at all, and usually do. Just brown the cubes on at least 2 sides, or all 4 if you have the patience. Set aside.
Heat the ghee over a low-medium heat. Add the onions and garlic and fry gently til the onions soften and begin to turn golden.
Add the turmeric, salt, garam masala, and coriander powder and fry about a minute longer.
Add the diced tomatoes and cook until they begin to soften.
Add 1/2 c of the whey and simmer for about 5 mins until the tomatoes become a pulpy sauce.
Add another 1/2c of whey and the peas, cover, and simmer until the peas are cooked. If you are using fresh peas from the garden, you may need to add another 1/2 c of whey to fully cook them (frozen peas will cook faster).
Remove the lid, add the paneer, and cook, stirring gently, until the remaining liquid has been absorbed by the paneer or has cooked down.
Garnish with chopped cilantro and serve with rice, puri, or chapati.