Rinse and peel off the Karela very well.
Chop Karela into thin or small pieces in any pattern of your choice. Here I have keep it ring shaped. While chopping, remove all the seeds very carefully.
Chop the onion and tomatoes (if applicable).
Heat mustard oil in a pan or kadhai. Temper the oil with panch phoron and dry red chilly.
Add chopped onions. Fry it until light golden. If in a hurry, you can add a pinch of sugar.
Mix chopped Karela with the onions. Saute for a minute.
If you want to add tomato, you can add at this point. I've not used tomatoes since it was not available in my kitchen when I was preparing this recipe.
Now add turmeric and salt as required. Mix all well.
Stir the mixture with spatula very often so that the vegetables do not stick to the bottom of pan.
Try to cook the sabzi by covering the pan. This way the sabzi would be cooked in less time.
Let it cook for 10-12 minutes on low flame.
Sprinkle dry roasted cumin powder. Give it a nice mix.
Cook for another 1 minute.
When the sabzi is ready, turn off the flame. Serve it with rice along with dal or rotis.