1.Preheat oven to 180°C/160°C fan-forced. Line shallow oven tray with baking paper.
2.Peel sweet potatoes; place in bowl of cold water with juice to prevent browning. Cut potatoes into thick slices, return to water. Drain potato; pat dry with absorbent paper.
3.Place potato and onion on tray; drizzle olive oil over vegetables. Drizzle sweet potato only with maple syrup. Sprinkle with salt.
4.Roast vegetables with turkey about 40 minutes or until tender and browned.