Ingredients

Step by step

1. Put the plums and sugar in a large saucepan, mix thoroughly, cover and leave to macerate overnight. This draws out the juices and shortens cooking time, giving a fresher flavour.
2. The next day, put a few saucers in the freezer, ready to test for setting point. Put the pan on the hob, add the bay leaves and lemon juice and heat gently over a medium heat, stirring occasionally, until the sugar has completely dissolved, without allowing it to boil. Remove the bay leaves and put one in each jam jar (discard the others).
3. Turn the heat right up and bring to a rolling boil. Boil for 10 minutes, stirring often, until a jam thermometer is just below 105°C. If the fruit isn’t breaking down, mash with a potato masher. If you don’t have a thermometer or want to double check, let the jam boil for the full 10 minutes, then remove from the heat. Spoon a little onto a cold saucer from the freezer, and tip to spread it and cool quickly. Push it with your finger and if the top wrinkles, it’s ready. If not, boil for another 2-3 minutes and test again.
4. Once at setting point, take the pan off the heat and stir the butter (if using) through the jam to get rid of any scum (or simply lift off with a spoon). Leave the jam to settle for 10 minutes before potting up, as this ensures the fruit is distributed evenly. Spoon the hot jam into warm sterilised jars, then screw the lids on tightly while the jam is still hot. The jam can be eaten straight away, or kept in a dark, cool place for several years. 
   Tip

   This recipe is vegan and dairy-free if not using butter