Tree full of very tart plums...ideas

[frikadela01]

So the tree in our garden that has been barren for years has inexplicably produced an absolute fuck ton of plums this year. Unfortunately they are quite tart even when ripe.
Aside from my first ever attempt at jam next week, what can I make with them?

I'd love to do a Chinese style pl sauce bit ideally would like some thing that will keep longer than a few days.

Any ideas?

i was going to say jam, but I see you are already doing that.
Fruit compote?
Alcoholic drink?

Plum chutney is lovely.
I picked loads last year, and simply cooked and froze them, without stones, and then use to make plum and apple crumble now and again.
You could make wine, maybe?
To freeze, get a few rectangular plastic boxes, put a freezer bag in each, fill up with plums - cooked and stoned take less room. Tie and freeze, then when frozen, remove bag from box, so you can reuse box. Stack frozen blocks like bricks along one wall of the freezer.