Heat the slow cooker to low. Tip in the cabbage, then scatter in the mixed spice, sugar and some salt and pepper. Pour in the vinegar, stir well, then dot over the butter. Put the lid on and cook for 3 hrs 30 mins until starting to soften

Remove the lid and cook for another 30 mins until the cabbage is very tender and sticky, and the liquid has reduced. Taste for seasoning and serve. Once cool, will keep covered and chilled for up to three days, or frozen for up to two months. Reheat in the slow cooker or a pan over a medium heat until piping hot.