- 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.