A simple prickly pear jelly preserves these beautiful cactus fruits for year-round eating.
Peel and chop prickly pear fruits. Add them to a saucepan with enough water to cover. Simmer for about 1 hour, adding more water to keep them covered.
Pour the fruit through a fine mesh strainer and measure the resulting juice. You should have about 4 cups of juice from 8-10 fruits.
For every cup of juice, add 1/2 cup lemon juice and 1 cup sugar. Reserve a small amount of sugar about 1/4 to 1/2 cup for mixing with the pectin powder.
Add calcium water and bring the sugar/juice mixture to a boil. Simmer for about 5 minutes.
Mix the pectin powder with the remaining sugar. This is important because added on its own the pectin will clump instantly on contact with a liquid. Stir in the pectin/sugar mixture and simmer for another 2 minutes.
Pour the prickly pear jelly into prepared canning jars, leaving 1/4 inch headspace.
Store jars in the refrigerator, or process in a water bath canner for 10 minutes.