Chop the onions and cut the parsnips and carrots into strips.
In an oven-safe frying pan (or saucepan), heat a drizzle of olive oil. Add the onions and the parsnip and carrot strips. Let them saute while you cut the squash.
Cut the squash into rounds and the apples into quarters.
Once the squash is cut, pour 2 tbsp. of cider vinegar into the pan. Let them saute for 2-3 minutes, then add the squash rounds. Place the apple quarters and the sausages on top. Drop an olive oil drizzle, salt and pepper.
Take it to the oven for 30 min. Take the pan out, pour 2 Tbsp of maple syrup and return it to the oven for more than 5 min.