Slather it on ricotta toast, spoon it over pancakes or stir it into oatmeal—this jam will keep for 2 weeks in the fridge!
Slice a shallow X into bottom of each plum. Blanch in boiling water 1 minute; transfer to ice water. Peel, pit and chop. In saucepan, bring all ingredients to a boil over medium-high. Cook, mashing with potato masher, until jammy, about 8 minutes. Let cool; refrigerate overnight to thicken.