Before you start, sterilise your jars and put a plate in the freezer to chill.
Tip the berries, lemon juice and sugar
into a preserving pan. Gently heat,
stirring occasionally with a wooden
spoon, until the sugar has melted and
fruits are juicy.
Bring to the boil and boil rapidly for
5 mins. Remove from the heat and drop
a little of the mixture onto the chilled
plate. Push your finger through it; it
should wrinkle and have set like jam.
If it doesn’t, boil for 2 mins more,
then test again and, if necessary,
keep repeating until it’s ready.
The top of the jam may look like it
has sediment on it, but if you stir it well
as it cools, it should disappear. Allow
to cool and settle for 10-15 mins before
ladling into sterilised jars and sealing.
The jam will keep unopened for 1 year
but, once opened, store in the fridge.