In a medium saucepan take oil

Turn the gas on and let oil heat for 10 seconds or so. Add mustered seed and cumin seeds. Now let them crackle. Keep the lid on to avoid mustered seed popping out.
Once they all are cracked, add ginger, garlic and chilli paste. Put the lid on quickly again for 10 seconds or so. Lift the saucepan and stir while lid is on.
after 10 or so seconds Add dry spices and cook all spices for a 20/30 seconds.
Now add potatoes and aubergine Stir well to make sure all spices and vegetables are mixed well. Now add 1/2 cup of water and let it cook for 10 min.
Now add chopped tomatoes and stir well again. Let it cook for further 5 min.

if using Garam Masala and corriender add now if not serve with rice and youghurt curry or chapati