Wash and cut beef into 2 cm cubes. Mix tamarind with water and remove seeds. Place tamarind water in a pan, add chilli powder, pepper powder, salt, turmeric, cinnamon stick and lemon grass and mix well. Add beef cubes and simmer over a medium heat until the meat is tender and the gravy has thickened. Remove the cinnamon stick before serving. From "A taste of Sri Lanka" by Indra Jayasekera, Isbn #962 224 010 0