Wash the damsons and place them into a large baking dish along with the brown sugar. Place them in an oven pre-heated to 180°C and roast for 40 minutes.
Remove from the oven and set aside until cool enough to handle.
Pass the damsons through a sieve into a large preserving pan. Pick through the pulp to remove all the stones, placing the stones in a large jug. Add the remaining stoneless pulp into the preserving pan.
Fill the jug filled with stones with the 600ml water. Swirl around so all possible damson juice is loosened from the stones.
Pour the water through a sieve into the preserving pan. Finally, discard the stones.
Zest the oranges, setting aside the zest until the very end. Then juice the oranges. Add the orange juice to the preserving pan, along with all the spices.
Bring to a boil and add the granulated sugar, stirring to dissolve.
Once the sugar has dissolved add the lemon juice. Bring to a rolling boil.
Boil the jam for about 10 minutes until the temperature reaches 104°C or passes the saucer wrinkle test*.
Remove from the heat, stir in the orange zest and decant into sterilised jars*.
*The saucer wrinkle test basically requires you to put about 5 saucers in your freezer when you begin making your jam. Once you think the jam might be ready then you can double check by removing a saucer from the freezer, dropping a teaspoon of jam on it then placing the saucer in the fridge. After about 30 seconds remove the saucer and push the jam with your finger. If it wrinkles up it’s ready, if it just pools back into the space your finger has left then it needs more bubbling time. Boil it another couple of minutes then turn off the heat and then test again with another saucer.*To sterilise the jars place the very clean jars you would like to use in an oven pre-heated to 140°C for 20 minutes. Sterilise the lids by dropping them into a saucepan of boiling water for 10 minutes with a splash of vinegar. I don’t sterilise my lids in the oven as they tend to ruin.Yield 12 200g jars