Heat oil in a pan and add cumin seeds. Let it crackle for few seconds
Mix into chopped (canned) tomatoes and red chilli powder. Cook for few more minutes until all gravy combined and oil starts to leave the sides. Keep it aside.
Preparing subji/curry
Heat the oil another wide pan add mustard seeds first

Followed by cumin seeds and asafoetida. Add curry leaves and stir. Add chopped potatoes. Add into salt to taste and add ½ cup water. Stir. Cover the lid and cook on slow-medium heat.

Cook for about 8-10 minutes. The potatoes should be cooked till fork tender but still holding their shape.Add now with all chopped greens. Season with all spices. Give it a stir.

Add the prepared gravy and mix it well. Adjust the consistency, not too thick or runny. Add few tablespoons more water if needed.