While any plum will make delicious butter, we recommend damson or Italian plums. Please read How to Process.

Weigh and record the weight of:

Wash, quarter, and pit the plums and place in a large pot along with:

Bring to a boil, cover, and reduce the heat to simmer until the plums are very soft, about 15 minutes. Run the pulp through a food mill fitted with the medium disk. Discard the skins and measure the puree. Transfer the puree to a pot or roasting pan and add:

Bring to a boil and simmer over medium-low heat or bake in a 300°F oven, stirring every hour, until the butter is thick and can be mounded on a spoon. It should not exude any thin liquid, but keep in mind that plum butter will not be quite as thick as apple butter.

While the butter cooks, prepare a water-bath canner, gather all your canning equipment, and have ready clean, hot half-pint jars (you should get ¾ to one half-pint jar of finished butter for every 1 cup puree).

Ladle the butter into prepared jars, leaving ½ inch headspace. Wipe the rims. Place lids on jars and screw on rings until fingertip-tight. Process for 15 minutes. Let cool completely and store as directed.