2lb.stoned halved ripe plums
1 1/2lb granulated sugar
Simmer the fruit in water until tender. Meanwhile, put the sugar into a bowl & place in a pre-heated oven (gas4. 350*F 180*C).When the plums are cooked, add the hot sugar, tipping the pan & stirring gently until the sugar is dissolved completely -it's very important no sugar crystals should be left or the jam will be sugary. Test this by coating the back of a wooden spoon.
As soon as it has dissolved, turn the heat to high & boil rapidly for 10 minutes.
Remove from heat & test a little on a very cold plate.When it is cool, push the jam with your finger. If a crinkly skin forms, the jam is ready. If not ready, boil again for a further 5 minutes.
Repeat as necessary.Ignore any scum that may form during cooking but,if any remains,skim & add a small knob of butter.
Leave jam to settle for 15 minutes to settle, then pour into warm, sterilized jars, fill right to top then cover with a waxed disc & seal tightly.