boil the liver in plenty of water and a couple of teaspoons of anniseed powder. Take it out of the pan and pat dry on kitchen paper. Slice thinly then place on a tray and bake on a very low heat for a couple of hours, until you can break small pieces off. I've been told that you can also keep the water that the liver was boiled in to mix in with the dogs kibble. Once cooked break up into small pieces and bag up for the freezer or will keep in the fridge for a few days.