Contributor’s Note: An old recipe for roasted bear haunch begins, "First, kill a bear." In the case of cactus jelly: First, steer clear of the wild pigs. Don't have any truck with javelinas. It's better not to share the prickly pear patch with those nasty smelling, mean little tuskers.
Second, know your cactuses or buy your tunas (prickley pears) at the supermarket. There are a few poisonous species. The sap of the Pencil cactus, for instance, is toxic. It can burn and blister skin and, if eaten, can cause diarrha, even shock. Chain Stores wouldn't be taking any chances, so it's better to trust the grocery stores than to pick your own.
6-8 large Prickly pears (a couple on the less ripe side). Pears can be anywhere from 2 to 6 inches long, so other ingredients have to be apportioned with that in mind.
3 cups sugar
1/2 cup lemon juice (Lemon juice provides the acid necessary to help set the pectin and sugar when the mixture cools)
6 ounces liquid fruit pectin, such as Certo, because cactus fruit doesn't have much natural pectin
Put prickly pears in a large kettle and cover them with boiling water. Let the pears stand 2 to 3 minutes. Pour off the water. The spines on the pears will be softened.
Peel the pears, cut each into 4 to six pieces, but don't try to take out the seeds. Put the pieces into a medium-sized kettle, cover with water and boil for 5 minutes at high heat. Pour the mixture through cheesecloth. Drain as much juice as possible and discard seeds.
Combine the drained cactus juice, (which should measure about 3 cups) with the sugar and lemon juice into a large kettle. Bring it to a rolling boil. Reduce heat to medium and add liquid pectin. Cook mixture 9-12 minutes, or until it starts to thicken. Skim off foam, if there is any.
Pour the mixture into hot, sterilized, half-pint canning jars. Follow manufacturer's directions on sealing. Always put sealed jars into boiling water for five minutes to kill any roving bacteria.
Cactus jelly may jell soon after it's made or take as long as 3 weeks. Don't give up on it.
If you forgot to put in a few greener tunas and don't get the jelly to set, even with the commercial pectin, you get some mighty nice syrup. Not that anybody has it in for peccaries, but it tastes great on pork chops.