Meanwhile, soak the basmati rice for 30 minutes in cold water, then drain well. Add the butter to a pan along with the rice and fry for a couple of minutes. Add 300ml of boilling water, mix well and cover with a lid. After about 5-7 minutes, when all the water has been absorbed, remove the pan from heat. Cover the pan with a clean tea towel then put the lid back on. Rest for 5 minutes before serving.