For the rhubarb-blueberry jam, blanch all fruits and puree for max. 20 seconds with a hand blender. Immediately in the pot add the jelling sugar and simmer for about 4-6 minutes. Add citric acid and a dash of rum. Check the jelly in between.
Wash out the jars while hot. Add a dash of rum to each jar. Increases the shelf life. When the jam has simmered for 4-6 minutes, fill hot into the jars, seal immediately and turn upside down.
Allow the rhubarb blueberry jam to cool and store in a cool, dry place.
Preparation Tip:
The rhubarb-blueberry jam also tastes great in cakes and pies.