Separate the red fleshy calyxes from the seed pods and wash thoroughly.
Place seed pods in a saucepan, cover with water (less is water is better than more), bring to a boil, then simmer for 30-40 minutes until soft.
Strain the liquid through a fine strainer, reserving the pectin-rich liquid.
In a large saucepan, combine calyxes with the reserved pectin liquid and extra water if needed.
Bring to a boil, then simmer for 20-30 minutes until calyxes are soft.
Remove from heat and measure the volume of the cooked pulp.
Add an equal amount of sugar to the pulp (1:1 ratio).
Optional: Add a squeeze of lemon juice for extra pectin and flavor.
Return mixture to low heat, stirring until sugar dissolves completely.
Bring to a rapid boil and cook for 20-30 minutes, stirring frequently.
Test for setting point by placing a small amount on a cold plate. If it wrinkles when pushed, it's ready.
Once set, remove from heat and pour hot jam into sterilized jars.
Seal immediately and allow to cool at room temperature.