12 oz fresh raspberries
4 large black plums, finely chopped
3 tablespoons powdered pectin*
2 cups sugar
Use a potato masher to gently mash the raspberries. It should yield 1 cup crushed raspberries. Repeat with the plums to yield 2 1/4 cups.
Evenly sprinkle the bottom of the Ball Jam Maker with the pectin. Spoon the fruit in a relatively even layer over the pectin. Press the jam button. You will hear a beep at 4 minutes. Sprinkle the sugar over the fruit mixture while the machine is still running. Cover and let it do its thing until it beeps again. Press the cancel button and unplug the machine. If not using a Ball Jam Maker, make the jam on the stovetop using the traditional method as seen in this recipe.
Ladle the jam into prepared jars leaving 1/4 inch headspace. Process in the hot water bath for 10 minutes.
Yield: about 4 8-oz jars. (I was just slightly under so I canned 3 8-oz, 1 4-oz and had a bit leftover that I just ate)
*I recommend these jars of "flex" batch pectin. 3 tablespoons equals 1/2 of a pouch of boxed pectin.
Note: A great source for canning information is the Blue Book guide to preserving. I highly recommend it for learning how to can. Here is a bunch of other canning books and equipment I find useful.