Ingredients:
2 kg of guavas
1½ kg of cane sugar
juice of 1 lemon
finely-grated zest of 1 lemon
Water
Method:
Wash the guavas then cut into pieces (no need to peel). Place the fruit pieces in a large saucepan or cast iron casserole (Dutch oven). Three-quarter cover the fruit with water then bring to a boil, reduce to a simmer and cook, stirring occasionally for about 40 minutes (top up the liquid level with boiling water as needed during this time).
At the end of this time, when the guava is very tender, turn the liquid into a fine-meshed sieve (or jelly bag) and let it drain into a bowl. Do not be tempted to squeeze or press down on the pulp, or the jelly will be cloudy, just let it drain naturally for about 6 hours, leaving the peel and seeds behind.
Return the guava juice to the pan and add the sugar, lemon juice and lemon zest. Place over high heat and bring to a boil. Cook for about 10 minutes then test for setting (place a dollop of the jelly on a plate chilled in the fridge, if the jelly forms a skin when you shift it with your finger it's at the setting point). If it's not ready boil for a further five minutes then test again.
Take the jelly off the heat, allow to cool slightly, then pour into sterilized jars that have been warmed in the oven. Seal the jars and allow to cool then store. Once opened store in the refrigerator.