These plums are not exactly the same variety as the ones we had on the tree in our own back yard, but they are similar. Ours ripened a few weeks ago and were immediately devoured by birds. The neighbors' plums weren't really quite ripe yet, but I picked some late last week anyway. They aren't a "freestone" variety, so I figured I had two options: either bake them in a clafoutis, pits and all, or make jam or jelly with them.
I ended up making jelly, which is something I had planned to make with our own plums before the birds stole them all. It turned out to be pretty easy. I just rinsed the plums, put them in pot, covered them with water, and simmered them until they burst and released their juice. I crushed them a little with a potato masher as they cooked. They simmered on low heat for 30 to 45 minutes.
Then I dumped the unpitted plums into a colander lined with a kitchen towel, letting the juice drip into a bowl for an hour or more. I ended up with a good liter of juice. I went down to get a kilogram bag of sugar out of the cellar, and discovered that I had a bag of sucre spécial gelées — sugar that has pectin mixed with it. So I followed the instructions on the bag: dissolve one kilo of sugar into one kilo of fruit juice. Bring that mixture to a boil and let it boil for five minutes or more. It worked! I ended up with five jars of thick jelly.
Not only did I pick little red plums at the neighbors', but I also picked about a kilo of the slightly larger yellow plums that are called mirabelles. Now I have to figure out what to do with them. They're sweeter than the red plums. Maybe I'll make preserves, but I'm letting the mirabelles ripen a little more before I do that.