Place the blackberries and spices in a sauce pan with about 2 tablespoons of water (just enough to prevent fruit from sticking). Bring to a simmer, cooking until the berries are tender and juicy, mashing with the back of a spoon or potato masher.
Run the berries through a food mill.
Return the berries to a pan and add the lemon juice; heat through, stirring often.
Add sugar, stirring until dissolved.
Turn up the heat and boil rapidly until the jam has reached the setting point (holds its shape when a spoonful is put on a chilled plate).
Pour hot jam into sterilized jars, leaving ¼″ headspace, cover with sterilized lids and rings.
Process in a hot water bath for 10 minutes.
Remove from water bath and let jars cool on a kitchen towel. If lids snap, jars are sealed; if they don't snap, refrigerate the jar.
Notes
This recipe filled three one-cup jam jars, with a bit of extra that went in the fridge. Put the water for the water bath on to boil before you begin cooking the berries; put the jars and lids in boiling water for about ten minutes to sterilize them. Leave them in the water until just before you fill them.
Recipe by Sprung At Last at https://sprungatlast.com/2014/09/spiced-blackberry-jam/