Heat a small frypan over medium heat. Add the coriander seeds and toss gently until the seeds start to colour and become aromatic. Remove from the heat, allow to cool then grind to a fine powder.
Place the beef in a large bowl and add the ground coriander seeds, chilli powder, turmeric, curry powder and jaggery. Mix well to ensure the beef is evenly covered with the spices.
Add the tamarind water, onion slices, green chilli and tomatoes and mix well.
Cover the bowl and refrigerate overnight.
to cook
Place a large pan over medium heat and add the oil.
Add the curry leaves, mustard and fenugreek seeds, cassia stick and cardamon pods to the oil. Stir until fragrant and the mustard seeds start to pop.
Reduce heat to low, add the onion slices and sprinkle with the salt. Fry gently until the onions soften and become golden-brown. This will take around 10 minutes.
Add the ginger and garlic, then gently fry, stirring continuously, until the raw garlic smell has gone. This takes around two minutes.
Increase heat to medium and add the marinated beef and any accumulated liquids and spices. Mix well and fry for five minutes, or until the beef is evenly coloured.
Add ½ cup of the coconut milk and the hot water to the pan and allow to come to a simmer. Reduce heat to very low, cover the pan with a lid, and let the beef simmer for 1½ hours, stirring occasionally. If the curry is drying out add a little more water, one tablespoon at a time
When the meat is tender, add the remaining coconut milk and mix well. Increase the heat slightly and gently simmer the curry, uncovered, for further 20 minutes or until the gravy thickens.
Remove from the heat and serve.
notes
If you cannot find Sri Lankan curry powder use a good quality brand from the supermarket. The curry powder provides a depth of flavour and aroma.Cut the beef into medium sized pieces - 3cm or 1½ inches.