Rogan josh is one of the better known Indian classics, and this fiery lamb or mutton dish from the Kashmir region of India is now popular all over the world. My version stays very close to an authentic Hindu-style recipe, but I have tweaked it to make a rich and spicy slow-cooked dish that is perfect for chilly winter days. There are several versions of rogan josh in existence, but the two most common are the Kashmiri Pandit (Hindu) version and the Muslim, or Mughal, version.