Like most spices coriander is best if purchased as whole seeds and ground as needed. If allowed to sit in the meat mixture for this dish as instructed above all that's necessary is to crush the coriander seeds on a plate with a large spoon. Sunflower seed butter is available in some whole foods stores in North America. Its use in this dish is an innovation rather than a traditional ingredient. Try substituting peanut butter, walnut butter, or other seed butters also. Serve on a bed of rice or couscous topped with diced tomato.