1 kg Blackberries
1 kg Sureset Sugar
Juice of 1/2 Lemon

The important thing with this recipe is not to make jam with more than 1 kg of fruit.

Put the blackberries into the pan with the sugar and the lemon juice.
Put it on the heat and then bring it to a rolling boil.
Once it is boiling time it accurately and let it boil for exactly 4 mts.
Have ready 4 X 1lb. Jam pots which you have washed well and dried in a hot oven to sterilize.
Once the 4 mts are up take the jam off the heat and push it through a sieve into a clean bowl (use the back of a ladle to push as much as possible through).
Ladle it into the jam jars and cover in the usual way.
(You can of course omit the sieving process and the jam will still work).