As far as I know, the method of making dal tadka and dal fry is a bit different. In dal fry, your pressure cooks the only dal first and then temper it with onion, tomato, whole spices, and few other aromatic spices. Whereas in dal tadka, you cook dal, onions, tomato, ginger, and green chilies in a pressure cooker and then tempered with cumin seeds, ghee, garlic, and red chilies.