I used Damson plum jam bought from a local orchard. I agree that it was a bit more bitter than I like, but think it was more about balancing the lemon juice and simple syrup. The jam with apple brandy is fantastic.

I did actually have a homemade damson jam and this was delicious but it /definitely/ had too much lemon. Maybe the original recipe uses a very sweet damson jam?

Only had Podravka “plum spread” - not sure how close it is to damson? Tasty and refreshing but not quite the depth of flavour I was hoping for.

I'd reduce the lemon a bit here *OR* I used the wrong jam (bonne maman strawberry rhubarb)