Add the rhubarb heavy-bottomed saucepan or Dutch oven, along with the sugar, water, a pinch of salt, and cinnamon (if using). Stir well to combine.
Heat over medium heat, stirring constantly, until the mixture begins to boil.
Once a boil is reached, reduce the heat to low to maintain a low simmer.
Cook uncovered for 10 minutes, stirring occasionally, or until the rhubarb is soft but not mushy.
Remove from the heat and stir in the vanilla extract.
Serve warm, or chill and serve cold if desired.