Place the persimmons in a food processor and grind until smooth.
Place the persimmon puree, sugar, lemon juice, and zest in a small saucepan. Bring to a boil, then reduce the heat to low and simmer for about 15-20 minutes, stirring occasionally.
Enjoy and refrigerate or freeze any leftovers.
Notes
If you feel it needs to be thickened you can dissolve 1 Tablespoon of cornstarch into 2 Tablespoons of water, then pour the mixture into the jam. If you feel it needs to be thinned out, you can add more lemon juice or just a bit of water and whisk.
Yield will depend on how large or small your persimmons are in size. We usually get anywhere from 6-8 ounces.