This is based on Delia Smith’s recipe for apricot preserve from her classic book Delia Smith’s Summer Collection: 140 Recipes for Summer. Peaches contain less pectin than apricots so it takes more boiling to get this to set. It’s delicious when you do though – a sweet, sticky summer jam.
1kg white sugar
juice of a large lemon
teaspoon of butter
Twelve hours before you want to make the jam, slice the peaches into pieces and remove the stones, reserving them for later. Put the fruit in a large pan with the lemon juice and sugar. Cover with a lid and leave for twelve hours to draw out the juice and toughen the fruit so it keeps its shape. Crack the peach stones with a nutcracker to remove the kernels. Put them in a small pan of boiling water for a couple of minutes, then drain them and slip off their skins. Reserve the skinned kernels to add to the preserve later.
Put the pan over a medium heat until the sugar is completely disolved – about 20 minutes. Pour some over the back of a spoon to check there are no granules remaining. Then turn up the heat and let the mixture boil rapidly – a rolling boil for about 40 minutes, stirring occasionally to prevent it sticking.
Put a teaspoonful of the preserve onto a cold plate and put it in the fridge for a minute. Push your finger through the jam – if it forms a crinkly skin it’s set. If not, boil for another 10 minutes. Test again. When it’s set, remove from the heat, add the butter to disperse any scum that’s formed and add the reserved kernels. Let it cool for 15 minutes before pouring it into the warmed sterilised jars*. Seal while still warm and label the jars when cold.
* Wash in hot, soapy water, rinse and heat jars in the oven at 150 degrees C, fill while still warm. Boil seals and lids in a pan of water for a couple of minutes. Remove with tongs and allow to dry.