Heat the oil in a pan on medium heat. Once hot add mustard seeds and let them splutter. Then add cumin seeds and let them sizzle a bit.
Add curry leaves and chopped green chilies. Saute for 30-40 seconds.
Add hing and turmeric powder. Immediately add cabbage, peas and potatoes. Mix well.
Add salt, red chili powder and coriander powder. Mix well so the spices are evenly coated with the veggies.
Cover and cook for 12-15 minutes or until veggies are fork-tender. Do stir two-three times in between and make sure that shaak is not sticking to the bottom of the pan.
Once potatoes are soft and tender, turn off the stove. Keep cabbage sabzi pan covered until the time of serving.
Notes
Slightly undercooked & crunchy cabbage or Completely cooked soft cabbage?
If you like your cabbage to be on a little underdone side then keep the potato pieces smaller. So potatoes get cooked and cabbage still stays crunchy.
If you like soft and cooked cabbage then keep the potato size as shown in the pic. Here I have used cabbage, peas and potatoes.
Variations:
Follow the same procedure only for cabbage or cabbage-peas or cabbage-potato.