Heat oil in a pan or a kadai.
Splutter mustard seeds.
Add cumin seeds, fenugreek seeds and curry leaves.
Add onions, green chillies and garlic.
Fry well, until golden brown.
Add tomato and fry, till the tomato blends well.
Add tamarind water and allow it to boil.
When it starts to boil, add turmeric powder, chilly powder and coriander powder.
When all the ingredients get cooked well and start emiting a nice aroma, add the coconut milk.
Allow it to boil for a few more mins.