This is a lovely jam that sets well and ends up clear and glossy, a light burgundy colour. Apart from the occasional piece of plum skin, it is more like jelly than jam. This recipe makes several jars, how many obviously depends on size but I always include several smaller jars so I can give them away as gifts without it causing me too much pain. I have succeeded with making half the following recipe and also made it without preserving sugar. The lemon zest and juice helps the set and adds a sharpness that I like.
Slather it on buttered toast, pikelets, muffins or crumpets. Second to apricot and bramble, this could my favourite jam although I’ll probably think of some others in a minute.
2 kg plums
2 juicing oranges
1 large lemon
2 x 325g soft brown sugar
1 kg preserving sugar
Using a small sharp knife, slice the flesh off the stones in big pieces, say 3-4 per plum and cut the pieces in half. Place in a large pan. Use a microplane to zest the oranges and lemon very finely over the top. Add juice from the oranges and lemon, juiced through a sieve to catch pips. Add both sugars. Place over a low heat and stir continually using a long wooden spoon to melt the sugar. Once there are no more grainy sounds from the sugar scratching the bottom you can begin the proper cooking. Continue stirring over a medium heat until the liquid begins to clear and the plum skins colour the liquid. 10-15 minutes. Increase the heat and boil furiously, stirring in a figure of 8 to avoid sticking. It will soon subside and little bubbles form, becoming more syrupy. After about 10 minutes, check for set by dropping a splash on a cold plate/saucer. Push with the side of a finger and if it forms wrinkles it’s set. If not, continue boiling and stirring, trying again until obviously wrinkly. Take care not to over-boil or burn; the whole thing should take more than 20 minutes max. Allow to settle in the pan for a few minutes then decant into hot sterilized jars, add a waxed paper disc (or not), cover then cool. I do this outside; it takes a surprisingly long time. Label and put away.