I remember loving Margaret Mahy's Jam: A True Story, a picture book all about a family who make masses of plum jam - so much that they use it for everything, including reattaching tiles in the bathroom.
If they had wanted a recipe specifically for concreting with plums, I probably could have helped. Last night I attempted to make jam but managed to over-reduce the mixture to a point where it's more like solid plum/sugar mix. Not quite sure what to do about that just yet. I even took pictures in anticipation of a blog post, and in my head had already held a tea party where people complimented the jam and I was able to tell them I'd made it myself. Pride certainly comes before a fall.