I use the same recipe for plum jam and for greengage jam. The fabulous thing about plum jam is that you can cook them whole without needing to remove the pits – they float to the top when cooking and you simply lift them out with a spoon.
Allotmenteer caution: If you’re not sure whether your plums have plum worm you can halve a few of your fruit to check before you get cooking! It’s not nice to think of eating a fruity worm jam, so better safe than sorry.
Greengage jam turns a golden unctuous colour, like greened honey.
Victoria plum jam has a lovely pink tone.
Many recipes call for equal measures of fruit and sugar, but I reduce this to one measure to three quarters – eg 1 kilo of fruit and 750 g of sugar. Plain old granulated sugar is just fine – no need to use jam sugar or add extra pectin.
Warm the plums in a pan with a touch of water.
Once the fruit has softened (but not completely disintegrated), add the sugar and lemon juice. (I use the juice of a single lemon and keep the pips. Although pectin’s not required, I do bag up the lemon pips in muslin and hang it with roasting string into the boiling mass of fruit.)