We made this plum jam the other day from plums we picked off various trees in our neighborhood park and growing on the side of the road. It's good, a bit tart, but I like tart. I burned the first batch, so I watched the second one carefully and cooked it less than the recipe called for. It's the perfect consistency; I love the chunks of purple and yellow plums.
We had some plums leftover, so I used them to make a plum cornmeal galette. It was perfection. I ate the whole thing by myself in just over two days. Not a good few days for the old health, but oh--who can resist? The taste of summer gets me every time.
Find the galette dough recipe here, and a link to the Martha plum jam recipe here. She uses plums and peaches, but I used all plums. I found I needed some extra sugar and maybe two pinches of salt to counteract the added sugar. It was still quite tart, but tasted homemade and not sugary sweet like store bought jam.