My wife did most of the heavy lifting in making this sauce. I was more of an adviser. First she cut the plums in half and put them in a saucepan with just a pit of sugar.
After a bit of stewing and breaking them up with a wooden spoon it looked like the following.
That was looking pretty good but once you have made tomato sauce using a food mill you start to look for other things to put into it as well.
The finnal sauce ended up glossy and smooth. We left it mostly unsweetened for use in sauces and possibly sorbet. I am thinking of making a batch of barbecue sauce with some of it.
After all that we still had all these plums left over for fresh eating and cooking with.