Well where I come from, the white hard back fat is rendered down, and then at the end of the process apples pieces and onion slices are added, then poured into jars and very slowly cooled down. The crackly bits are minced, added some salt. Both are eaten on (sourdough or other dark) bread, some salt on top and absolutely delicious (although any heart specialist would probably have a heart attack when hearing this...). All last very well over winter in cool larder.
Also rendered lard very good for cooking, esp cabbages during winter, doughnuts etc etc.
Also useful for making soap...