Be sure to first read through my freezer jam tips in this post, right before the recipe. Then wash 5 half-pint (1 cup) plastic containers and lids with hot water and dish soap. Rinse and dry thoroughly.
Combine exactly 1 cup crushed strawberries, 1 cup finely chopped rhubarb, and orange zest in large bowl, and stir to combine. Add sugar and cardamom and stir well. Let stand 10 minutes, stirring every couple of minutes.
In a small saucepan over high heat, mix water and pectin. Bring to a boil, stirring constantly. Boil and stir for 1 minute. Add pectin mixture to fruit mixture and stir constantly for 3 minutes, or until sugar is dissolved and no longer grainy. If a few sugar crystals remain, that's ok.
Immediately fill containers to within 1/2'' of container tops. With a damp paper towel, wipe off the edges of containers. Immediately cover with lids. Let stand at room temperature for 24 hours. Jam can now be used, stored in the refrigerator for up to 1 month, or frozen for up to 1 year. Thaw in the refrigerator before using.
Notes
Basic freezer jam recipe from SURE-JELL, with adaptations from a farmgirl’s dabbles.
Nutrition information is automatically calculated by Spoonacular. I am not a nutritionist and cannot guarantee accuracy. If your health depends on nutrition information, please calculate again with your own favorite calculator.