Ghee is butter that has been slowly melted and cooked until the water is gone and the milk solids have been taken out (they often brown a little first). What is left is a clear golden fat. It keeps well, even without a fridge, and you can heat it hotter than ordinary butter without it burning. It is everyday cooking fat in much of India: for frying spices, for spooning over rice and dal, for sweets, and sometimes in temple offerings. It is usually made from cow’s milk, sometimes from buffalo milk. People who cook Indian food just say ghee; they only say “clarified butter” when they are explaining it to someone who has never heard the word. It is not the butter you spread on bread, and it is not margarine. It is also not “melted butter” in the simple sense — melted butter still has water and milk solids in it.