Roast vegetable crisps

1. Preheat the oven to 190°C, gas mark 5. Grease 4 non-stick baking sheets with a little oil.

2. Slice the sweet potato very thinly on a mandolin. You are looking for a thickness of about 2mm – not quite wafer thin but you should be able to see the light coming through the vegetable flesh when you hold it up.

3. Repeat the process with the parsnip and carrot, this time holding the vegetables at an angle to create elongated oval shapes.

4. Lay out a double layer of kitchen roll and pat dry all the vegetable slices.

5. Pour 3 tbsp of the olive oil into a large mixing bowl and add the vegetable slices, tossing to coat with the oil. Lay them all out in single layers on three of the baking sheets. 

6. Next slice the beetroot into rounds (preparing these last ensures that the beetroot doesn’t bleed into the other vegetables). Pat these dry on some fresh kitchen paper.

7. Add the last tbsp of oil to the mixing bowl, then toss in the beetroot. Once the beetroot slices are coated, lay these out on the last baking sheet.

8. Roast the vegetables for 20-25 minutes, turning the slices over after 10 minutes. Keep an eye on the vegetables as they turn from crisp to burnt quite quickly: the beetroot turns quickest so will need to come out after 20 minutes, but some of the other larger crisps will need another five minutes. 

9. Place the vegetable crisps on a cooling rack and season while still warm. Leave to cool. Store in an airtight container until ready to eat.