Method

• 1

  Wash the jam jars and place upside down in the oven at 100C/225F/Gas 1/2 to dry thoroughly. Place a small plate in the fridge for testing the jam later.

• 2

  Peel and cut the apples into blackberry-sized pieces and transfer to a preserving pan. Add the water and start to simmer gently. Add the lemon juice to the pan and cook until the apples are soft. Stir in the blackberries, then take off the heat.

• 3

  Still with the pan off the heat, stir in the sugar, until it has almost dissolved. You’ll know it’s dissolved when you don’t hear or feel the sugar scraping on the pan as much when you stir.

• 4

  When the sugar is almost completely dissolved, return the pan to the heat and bring to the boil. As it starts to boil, add the butter, which will help minimise and disperse any foam, which is a natural part of jam making.

• 5

  Bring to a rolling boil for 15 minutes. Don’t be afraid of the rolling boil; this is crucial for the jam to set.

• 6

  Spoon a little jam onto a chilled saucer, then, as soon as it is cool, run a finger through the jam so that the saucer is visible. If the finger line remains and the jam wrinkles it is ready; if not, boil a little longer and try again.

• 7

  Ladle into hot jars and fill until almost full. If you’re sealing the traditional way, cover the surface of each jar with a waxed disc, with the shiny side downwards. Rinse a cellophane circle with water then put wetted side uppermost over the top of the jar and secure with an elastic band. Label and leave to cool.

• PER SERVING: 2.5g FAT (Excluding extras)