Makes 716 (.3 .2kg)
4 lb (1.8kg) plums
1 pint (400ml) water
4 lb (1.8kg) granulated sugar
Cut plums in half following the line of the fruit, twist to separate and remove the stones. Put plums and water into a preserving pan and simmer gently for 10-20 minutes until fruit is tender. Meanwhile, crack 12 stones and remove inner kernels. Blanch the kernels for 1 minute, then drain and set aside.
Add the sugar to the plums and stir until dissolved. Bring to the boil and boil rapidly for about 15-20 minutes. Draw off the heat and test for a set. Skim the surface and stir in plum kernels they add a subtle almond flavour to the jam. Pour into warmed jars and cover.