Soak the bread in hot water to cover till it becomes a soft mush. Add the onions, crumbled stock cubes and seasoning, and mix well.
Heat oil or lard in a large baking tray and heat in a 200 C / Gas 6 oven. Once hot, place mixture in tray and return to oven, and cook for 1 hour. A skin should form on the top, then the edges should become crisp.