Kefalotyri(or Kefalotiri) (Greek: κεφαλοτύρι) is a rather har, salty yellow cheese made from sheep and/or goat's milk in Greece and Cyprus (cow's milk is not allowed), although, a similar cheese Kefalograviera, which is made with cow's milk, or a mixture of sheep and cow is sometimes sold outside Greece and Cyprus as Kefalotyri. Depending on the mixture of milk used in the process the color can vary between yellow and white. Being a very hard cheese, Kefalotyri is consumed as is, fried in olive oil or added to foods such as spaghetti, meat, or cooked vegetables. This is a very popular and well-known cheese, establishing its roots in Greece during the Byzantine era. It takes from two to three months to ripen.