Peel ripe persimmons and set aside. If persimmons are very ripe, it is easiest to cut the tops off and spoon out the flesh. If they are the Fuyu variety and you are using them in a less ripe state, a peeler or paring knife may work better.
Blend pectin and 1 cup reserved sugar and set aside.
In a large saucepan, add liquid, three pounds sugar, salt, thyme and persimmons. Bring to a boil and reduce heat to a simmer. Stir occasionally with a wooden spoon and rubber scraper. Halfway through, at about the 30-minute mark, add bananas followed by sugar/pectin mixture. Whisk periodically and continue to cook on simmer about 20 minutes, as the jam begins to thicken.
Remove from heat and remove the thyme. Mix using a hand mixer or blender until desired texture. Fill Mason jars leaving 1/4" headspace and wipe rims of jars, then place lid and ring on top to close jar. Jam can either be chilled, served warm or preserved using a hot bath canning process.
Hot Bath Process: Place the jars in a water bath making sure that the water covers each of the jars by 1 to 2 inches. Cover the pot, bring water to a boil and let jars sit in boiling water for 10 minutes. Remove the jars and place them on the dishtowel to cool.
*Note about persimmons: The Saijo variety (conical teardrop shape) must be extremely ripe when using or cooking with, otherwise they are very bitter. The Fuyu variety (squattier/flatter shape) may be eaten either hard or ripe. You may use a combination or one variety as preferred for this recipe.