1-2Tablespoons Honey or sugarto taste, see recipe notes
Filtered wateras needed
Make the wild plum puree by heating the wild plums in the oven, or freezing them and thawing to loosen their flesh. Transfer the plums to a colander over a bowl to catch the juice.
Allow the plums to cool for a bit until you can handle them, then mash with gloved hands, pressing the puree through the colander, mixing it with the plum juice.
Alternately, use a Squeezo-type food mill with a large enough hole at the end to accommodate the stones. Discard the pits and skin or save to make vinegar, compost, etc. Puree the plum mixture in a blender for a smooth consistency with the honey, sugar, and salt, or use a hand blender.
The plum sauce should have the consistency of smooth tomato sauce, but should not be thick like ketchup. If needed, thin the sauce with a bit of water, or cook gently to thicken it if it's too thin. Double check the seasoning and adjust as needed, then serve or refrigerate. The puree will keep for a week in the fridge or longer in the freezer.
Anywhere from 1-4 tablespoons of sweetener is fine here, depending on your personal tolerance for astringency. I suggest adding a tablespoon at a time until you like it.