ml Tamarind Juice (Extracted from 50gm tamarind)
Roast all the ingredients used for spice powder one by one and grind into a fine powder.
Heat some oil in a pan. Add Mustard seeds and when they splutter add Red chillies, Onion, Garlic and Curry leaves. Cover with a lid and cook on a medium flame till the onions become light golden brown.
Add chopped Tomatoes, Salt and cook till the Tomatoes become soft.
Add Chilli powder and Coriander powder. Saute and then pour Tamarind juice in it and cook till it starts bubbling.
Drop the Sweet Potato pieces into it, adding required water. Close the lid and cook for 30 minutes. Now you can add Jaggery pieces (If you prefer more sweetness).
Garnish it with Chopped Coriander leaves and remove it from the fire. Serve it with hot Rice and Ghee.