Peel and slice 500 grams of onions into thin slices.
Heat 4 tablespoons of mustard oil in a pan until it reaches its smoking point, then reduce the heat to medium.
Add 1 teaspoon of cumin seeds to the oil and let them crackle.
Add the sliced onions to the pan and sauté until they turn translucent.
Add 2 finely chopped green chillies, 1/2 teaspoon of turmeric powder, 1 teaspoon of coriander powder, and salt to taste. Mix well.
Cover the pan and cook on low heat for about 10-15 minutes, stirring occasionally, until the onions are soft and golden.
Garnish with fresh coriander leaves and serve hot with rotis or parathas.