Put the sugar and 250ml water in a small pan. Warm over medium heat until the sugar has completely dissolved. Set aside to cool. Preheat oven to 100℃.
Wash and trim the rhubarb, then peel into long, even strips with a vegetable peeler. Put the cooled sugar syrup in a small bowl and submerge the rhubarb strips. Soak for 5-10 minutes.
Line a baking tray with paper and arrange the rhubarb strips in a single layer, not touching, smoothing them so they lie flat.
Bake until the strips are dried out and fairly crisp – they should be dry and not tacky to the touch. Avoid overcooking, as they will break when you try to curl them. Start checking after 15 minutes. Some slices will be ready before the others, depending on the thickness of the slice and how evenly your oven heats. This is actually handy if you don't have millions of wooden spoons, as you can curl them a few at a time.
After you have removed them from the oven work quickly, otherwise they will set. Curl round various implements – wooden spoons, cocktail stirrers (you need quite a lot) and leave to set for 10 minutes. If the rhubarb doesn't hold its shape, it needs a little longer in the oven. If it breaks or cracks, you have cooked it for too long.