In a heavy saucepan, combine all ingredients and let stand for 1 hour.
Bring to a boil over medium heat and simmer for about 1 hour or until rhubarb is translucent and the mixture has the consistency of a thick and syrupy mash. Stir frequently while cooking and especially at the end of cooking to prevent scorching.
Pour into three 250 ml (1 cup) jars. Cover and let cool. Refrigerate until completely cooled. Will keep for about three weeks in the refrigerator or freeze.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.