Finely chop the onion and fry it gently in the oil until its transparent, but not brown. Add the spices and stir round in the oil for a minute. Add the rice, stir to coat with oil then add the water. Bring to the boil then turn down to simmer for about 20 minutes. Add the turkey and cashew nuts and continue to simmer until the meat is hot, the rice is tender and all the water is absorbed.