In a pot heat mustard oil, add cumin seeds and fry for 30 seconds.
Add onion and fry for 2 minutes. Now add Ginger, garlic and chilli paste and fry for another 1 minute.
Add potatoes and fry for 3/4 minutes.
Now add tomatoes, all remaining spices and mix well. Cover and cook for 7/8 minutes.
At this point add chopped spinach. Give a good stir and simmer this covered with a lid on low for 5 minutes, then uncovered until the moisture from the spinach has been cooked out and there isn't any murky-coloured water left.