Peel your onion and halve it, then cut each half into thirds. Place in a roasting dish and add the sausages.
Core and cut the apple the same way and add to the dish, along with the squash. Give it all a stir to evenly distribute the ingredients.
Drizzle with the oil and vinegar, or vinegar and honey mix, and scatter over the herbs and black pepper. Bake in the centre of the oven for 40 minutes, shaking gently halfway through.