Yams are very healthy and they have a low glycemic value. But this dish will taste just as great with sweet potatoes too.
When mustard seeds start crackling rapidly, lower the heat and add the yams. Mix.
Add 4 cups of water, turmeric, cayenne pepper, hing, curry leaves and 1 tsp salt. Water should be about an inch higher than the contents.
Increase the heat to medium. Cook partially covered for 5 minutes.
Uncover. Add tamarind and chopped cilantro. Add this to the mixture in the pan.
Add 1 tbsp rice flour to a small bowl with half of cup of cold water and mix well. Add this to the pan on the stove.
Cook for 2 minutes or until yams are cooked but firm. Yams cook quickly. Check with a toothpick. Do not overcook.
If necessary, add more salt or cayenne as you wish and mix well.
You can use this as a gravy for any suitable main dish.