Add ingredients in this order - water, rhubarb then sugar. Note that this is a sweet rhubarb sauce. If you would like it a little tart, reduce sugar to ¼ cup.
Cook on medium heat, adjusting heat to keep it at a low simmer.
In a few minutes the rhubarb will release it's liquid and will fall apart into a sauce. If you prefer your rhubarb chunky, remove from heat at that stage.
Serve on ice cream, yogurt or pound cake. Some folks like it warm, I prefer mine at room temperature or cold.
Notes
StorageRhubarb sauce can be refrigerated up to 4 days in a sealed container. It can be frozen up to 3 months. If necessary, it can be frozen for up to 6 months, however, some of the flavor may deteriorate a bit.
Nutrition (I am not a nutritionist. These are estimates only)