...or plum jam / plum butter. Very popular and widely used in Austrian cooking. It is used as a filling (sweet dumplings, cakes, biscuits, etc.) and you can use it as a spread on your bread, of course. It also adds a lovely flavour if you use a little in your gravy. Or smear some Powidl on to your meat before roasting or grilling. You could also add some to your vegetable stir-fry with your other sauces. Basically, I think it is the bee's knees!
The pictures aren't great as the house is pretty dark again. We have the shutters on the windows and the curtains are all closed due to the stinking hot day. I also didn't feel very artistic when I took the pictures. No blemishes (ratty labels) were hidden.
It is very easy to make, especially if you have a slow cooker, because then you don't have to stir that often.
Use very ripe plums and you will not have to use any sugar at all!
My recipe, roughly:
Take approx. 4 - 5 kg plums (as unblemished as possible, of course) or as many as would fill the slow cooker. Wash, de-stone and cut into chunks. Throw straight into slow cooker.
Add about 1/2 litre water (or red wine). Adjust quantity if you have less or more plums.
Grind your favourite spices and add those. I ground 1 very long, thick cinnamon stick, 2 star anise, a few cloves and also added ground ginger.
Depending on how 'spicy' you like it, add more or less. For 4 to 5 kg you can add 3-4 teaspoons of ground spices. With this quantity you won't have the spices overpowering the Powidl. But you can add more or less spices, of course. All entirely up to your taste.
You could also add rum or whiskey or any alcohol of your choice, if you like.
I did have to add some sugar, as the plums were not totally ripe and a bit tart. So I added roughly 200g of sugar per kilo. You can add more or less. (Don't you like recipes like this!?)
Cover pot with lid and leave on until the fruit is soft. Then take off lid and let bubble on 'low' for hours or overnight, until you have reduced the fruit by nearly a third or so. Stir occasionally. You should end up with a lovely, thick, sticky, brownish-black mixture. Powidl! Fill into clean, sterilised jars. Enjoy!

You could play around with the spices. Chillies would be nice, too, I think. Or black pepper, etc.
Edit: I just remembered - I also added dried lemon & orange peel to the spices in the grinder. Whenever I squeeze a lemon or orange, I dry the peel and store it in an air-tight container. Very handy for all kinds of things.