In Tibet, these are made for weddings and other special occasions. Walnuts are always used, as they are plentiful and grown locally. Grains such as roasted barley and wheat are usually included, and hemp seeds often make their way in too, so do feel free to add some if you have them. Recent analysis of ancient pollen suggests that cannabis may have evolved on the Tibetan Plateau, and it has certainly been cultivated and used there for centuries.