Place prunes, 1 cup of wine, sweetener if you're using it (start with about 2 tablespoons, prunes are sweet!), and salt in a medium pot over medium-high heat. Bring to a boil, then reduce heat to low.
Simmer the prune-wine mixture, stirring frequently, until prunes begin to break down. If liquid gets low, add more wine about ¼ cup at a time. Using your stirring spoon, gently crush prunes against bottom and side of pot. The simmering process takes about 25 minutes.
Taste Pinot Prune Jam and adjust with additional sweetener and/or salt. Use a fork to further smash the prunes until you get to a jam consistency you like. It should have some texture. Do not blend or process the mixture; it will turn into a fruit butter, which isn't bad, but that's a different recipe.
Keep Pinot Prune Jam in a sealed container in the refrigerator for up to a week, if you can hold yourself back for that long. (This is not a "canned" or preserved jam so it should be refrigerated!)