Preheat the oven to 170 degrees(Fan Assisted)/Gas Mark 3
Cut the new potatoes in half
Cut the red onion in to chunky slices
Place the sausages, red onion, and new potatoes in a baking tray and toss in the oil
Sprinkle with the rosemary
Place in the oven and cook for 15 minutes.
Turn the food in the oil and cook for a further 10 minutes