Add chopped up onion (and any other vegetables), and peppercorns around the gammon
Pour in water (or your chosen liquid)
Place lid on slow cooker and set off for 4 hours on high, or 6-8 hours on low
Remove gammon from the slow cooker and leave to stand before carving (unless you are adding a glaze) - serve hot or cold.
Optional glaze: carefully remove any netting and the skin from the gammon, leaving the fat in place.Score the gammon joint and rub some honey over the top. You can also mix in some sugar and/or mustard. Place in a preheated oven (200°C/Gas Mark 7) and cook for 10 to 15 minutes
Notes
*You can swap the water for either; cola, apple juice, pineapple juice or dry cider.