Heat oil in wide heavy bottom pan.
Once hot, add mustard seeds. Once they are done popping, add asafetida.
Immediately add cubed potatoes and cauliflower florets.
Mix well, cover the pan and cook on medium heat until they are more than half way cooked. Mixing carefully few times in the middle so they do not get burn.
Once they are more than half way done, add all the spices listed above. Mix well.
Run frozen peas through hot tap water 2-3 times to thaw them. Drain them and add them to the curry. If using fresh peas, boil/strain/add them to curry.
Mix well carefully. Cover it and cook on medium heat for another 2-4 minutes.
Potatoes and cauliflower should be all the way cooked by now. Best way to check it by poking it with fork, if they are fork tender but not mushy, they are well done!
Garnish it with chopped cilantro. Serve it hot with plain phulka rotli, achar and papad!