Preheat oven to 225º. Line a sheet pan with parchment.
In a small saucepan, bring 1 cup water and sugar to a boil over medium-high heat; reduce heat and simmer until sugar is dissolved. Remove from heat. Add rhubarb and let steep for 4 minutes. Remove rhubarb from simple syrup and lie flat on prepared pan.
Bake for 15 minutes. Remove from oven and loosely wrap each piece around a wooden spoon handle. Bake for 10 minutes, and check for dryness. If rhubarb is still tacky, bake 5 minutes more. Gently remove from spoons, and store on paper towels in a sealed container until ready to use.
Notes
Note: If rhubarb doesn’t hold its shape after baking, return ribbons to the oven for a few minutes to further dehydrate.
Recipe by Victoria at https://victoriamag.com/rhubarb-mousse-cake-recipe/