Before you start, sterilise your jars (see
tip below) and put a plate in the
freezer to chill. Tip half the raspberries
into a preserving pan and add the lemon
juice. Mash the berries to a pulp over the
heat with a potato masher, then leave to
cook for 5 mins. Tip the cooked berries
into a sieve over a bowl, then once all
of the juice has drained off, firmly work
the pulp through the sieve with a
wooden spoon until you are left with
just the seeds.
Tip the juice and pulp back into the
preserving pan and stir in the sugar. Heat
gently, then add the remaining whole
raspberries. Bring to the boil, then boil
rapidly for 5 mins. Remove from the heat
and drop a little jam onto the chilled
plate. Now push your finger through it
– it should wrinkle and look like jam. If it
doesn’t, boil for 2 mins, then test again.
The top of the jam may look like it has
sediment on it, but I find that if you stir it
well as it cools, a little of this disappears.
Pour into the jars and seal. It will keep
unopened for a year, although the lovely
bright colour will darken a little. Once
open, keep in the fridge.