I started off by searching to see if something already existed. I found this recipe from Delectable Musings, and decided to use it as an inspiration. What emerged was a deliciously tart spread that tastes great on pancakes.
*Note: if you're new to canning, check out this great tutorial on Pick Your Own, or see another really great list of resources on Food in Jars.
Vanilla Balsamic Rhubarb Puree
Adapted from Delectable Musings
Makes 4 x 8 oz. jars of jam
7 c. or 1.5 pounds rhubarb, sliced into 1/2" thick slices
2 c. water
1.5 c. granulated sugar
1/8 c. vanilla extract
1/2 c. balsamic vinegar
Cook the sliced rhubarb with the water and sugar on medium-high heat until it starts to boil. Stir the mixture and reduce heat to medium-low. When the fruit has softened a bit (about 10-15 minutes), remove it from the heat and puree it in a blender or food processor.
Add the vanilla and vinegar to the puree and process until well blended. Pour into sanitized jars (leaving 1/2 inch space on the top), screw on lid(s) and let sit in a boiling water bath for at least 10 minutes (check the sites above for the optimum amount of time).
Remove the jars from the hot water bath. Let sit so that they cool on a towel for up to 24 hours before serving. Test that the canning has been successful by pushing down on the top of the jar. If the lid pops, it has not been successfully sealed, and it needs to be stored in the refrigerator.