This guava jelly recipe calls for ripe guavas, sugar, and cream of tartar. The guavas are washed, chopped, and boiled until the seeds separate out. The boiled guava is hung in a muslin cloth to collect the juices, which are then cooked with the sugar and cream of tartar on low heat until the syrup changes color and reaches the right consistency. The jelly is then filled into sterilized jars and is ready to eat.