Step 1 of 4
Make the jam
Soften the plums
Put the halved and stoned plums into a preserving pan with the water. Bring to the boil, then lower the heat and simmer until the fruit is very soft. NB If you don't have a preserving pan, you can use a large, wide, heavy-bottomed stainless steel stockpot or a wide casserole dish.
95°C (203°F) hob
Make the jam
Dissolve the sugar
Add the sugar to the softened fruit and stir until it has completely dissolved.
Make the jam
Boil to setting point
Increase the heat and boil the jam until it reaches setting point, using a jam thermometer.
105°C (221°F) internal temperature
Make the jam
Pot and seal
Spoon or pour the hot jam into hot sterilised jars, then seal with sterilised lids.