Try cutting them into smaller pieces (say halves/quarters) and browning them first. Then fry up some onion and add 1 tsp each of groung cumin, tumeric, corriander seeds, sweet paprika and a bit of garlic. Add all this to the slow cooker with some liquid - either beef or vegie stock, though not too much because remember slow cookers have less evaporation than overn cooking) and a tin of chopped tomatoes. About 2 hours before it is ready add some dried fruit such as apricots or figs (my favourite) and if you have it some chopped preserved lemon. Then serve with couscous made with half stock and half orange juice.