Jars of this ruby red jelly make festive holiday gifts. Attach cards to the jars letting the recipients know they can serve the jelly with warm corn bread, over grilled chicken, or with cream cheese and crackers.
In a medium saucepan combine jalapeno peppers, cranberry juice cocktail, and vinegar. Bring to boiling; reduce heat. Cover and simmer for 10 minutes. Strain mixture through a sieve, pressing with the back of a spoon to remove all of the liquid. Measure 2 cups liquid. Discard pulp.
In a 4-quart Dutch oven or kettle combine the 2 cups strained liquid and the sugar. Bring to a full rolling boil over high heat, stirring constantly. Stir in the pectin and, if desired, hot peppers. Return to a full rolling boil; boil for 1 minute, stirring constantly. Remove from heat. Quickly skim off foam with a metal spoon.
Immediately ladle jelly into hot, sterilized half-pint canning jars, leaving 1/4-inch headspace. If using, divide the 5 hot red peppers among the 5 jars. Wipe jar rims and adjust lids. Process jars in a boiling-water canner for 5 minutes (start timing when water returns to boil). Remove jars from canner; cool on wire racks. Jelly may require 2 to 3 days to set. Makes about 5 half-pints (70 one-tablespoon servings).