Remove the skins from the persimmons, chop into desired sizes, add sugar, stir to coat the persimmon, then let sit for about 20 minutes. When the water is drawn out, add the lemon juice and put it all into a sauce pan.
Set on medium heat, and carefully remove scum from the surface. When the scum is gone, reduce to low heat and continue stirring until the jam thickens. This should take about 30 minutes.
When it reaches a substantial texture, it's done. If it reaches a jam-like consistency, it will harden after it cools, so be careful not to simmer for too long.
If you want to keep a stock of it, sterilize jars by boiling the jars and lids for about 15 minutes, then upturn them on a towel to dry, then fill to the top while the jam is still hot.
If eating right away or giving a little to someone as a gift, you can fill plastic containers with jam after it cools.
Story Behind this Recipe
I received a bunch of persimmons from a friend, and when thinking of various ways to use them, I decided to make persimmon jam, since I've never had it before. After searching different recipes on the internet, I came up with my own version.
Persimmons are more tart than apples, so it only need a little sugar. You can use either firm or ripened persimmons, so give this recipe a try when you have lots. You could also grate or put them in a food processor for a smoother texture.