Melt the butter in a large saucepan and add the onions. Cook over a gentle heat for a few minutes until they have softened slightly. Add the meat and top with the potatoes and stock and season with salt and pepper. Bring the stock up to the boil.
Turn the heat down to as low as possible and put a tight fitting lid on. Cook for 2 hours, stirring occasionally to ensure it is not sticking or burning.
Note: Instead of cooking on the hob it is possible to cook in a low oven instead. (150C/fan oven 130C/ gas mark 3)
55g dripping or butter
2 large onions, sliced
900g potatoes, thickly sliced
150mls beef or chicken stock
225g leftover cooked beef or lamb, cubed
Serve with 3 Nairn's Rough oatcakes