1. Preheat oven to 220 °C. Lightly coat a large baking sheet with olive oil spray.
2. Slice peeled parsnips into chunky chips.
3. Bring a saucepan of water to the boil and add salt. Parboil the parsnip chips for 5 mins then drain well.
4. Combine the polenta, parmesan and black pepper in a large bowl. Toss the hot parboiled parsnip chips to coat.
5. Spread the chips in a single layer on the baking sheet and spray with olive oil. Roast for 15 minutes, then gently turn the chips over, spray with more olive oil spray, and cook for an additional 15 mins, or until the chips are golden brown.