Method
Heat the oven to 180⁰C (Gas Mark 4), then cut the sweet potatoes into roughly 2cm chunks and place on a baking tray. Drizzle them with 2tbsp of the oil, season well with salt and pepper and then toss together until well coated. Make sure the sweet potato pieces are well spread out on the tray, then roast in the hot oven for 30-35 minutes, turning once, or until the skin and flesh are soft and a little browned around the edges. While the potatoes cook, put the remaining tbsp of oil into a frying pan over a low-medium heat and fry the onions until soft; stir in the garlic and sage and add several gratings of nutmeg, then cook for a further minute. Tip the mixture into a large bowl and season with salt and pepper, then stir and leave to cool. Next, put the cooked sweet potato pieces into the bowl with the onions, then add the cranberries, bread and eggs and stir it all together until well combined (crush some of the sweet potato as you go). Use a little oil to grease a deep 30cm x 20cm baking dish, then tip the mixture into the dish and scatter the grated cheese over the top. Bake in the hot oven for about 25 minutes, or until golden on top and piping hot throughout.