Method

• Check over the greengages as you wash them and eat any that are so ripe they are squishy (they may spoil the keeping qualities of the jam)
• Throw out any that are damaged or mouldy
• Slightly under ripe fruit is fine
• Put the whole greengages into a pan with 250ml water and the vanilla pods
• Simmer quietly for around 30 minutes until the fruit is extremely soft
• Draw off the heat and stir in the sugar
• Keep on stirring until it has all dissolved, then return the pan to the heat and bring back to the boil
• Let it boil hard for about 10 minutes, by which time the stones should be rising to the surface
• Lift them out with a slotted spoon
• Keep on boiling the jam until setting point is reached
• Skim off scum, fish out the vanilla pods (rinse, dry and bury in a jar of sugar to make vanilla sugar), then ladle into hot sterilised jars, seal tightly and leave to cool