100g plain flour
1 egg , lightly beaten
1 medium onion , sliced
1 apple , sliced (no need to peel)
Tip the flour and a pinch of salt into a large bowl. Make a well in the centre and pour the beaten egg into it, with a splash of milk. Draw in the flour with a whisk, gradually adding the remaining milk.
Heat oven to 220C/fan 200C/gas 7 and grease a 15cm x 25cm ovenproof baking dish with oil. Arrange the onion, apple and sausages in the baking dish and season to taste. Cook for about 10 mins, until the onion and apple soften. Pour over the batter and cook for a further 30-40 mins. The batter should be well risen and golden. Serve with gravy and mashed potato.