1 kg ripe blackberries
500 g sugar
Juice of ½ lemon
1 tablespoon whiskey (optional)
1 tablespoon clarified butter (optional)
Rinse the blackberries in cold water and remove their stems. Tip them into a large saucepan along with the sugar. Gently heat. Do not add water. The blackberries will release enough juice. Stir frequently with a wooden spoon. At the beginning of cooking, while the sauce is still liquid, push the blackberries through a sieve to remove their seeds. Return the pulp and juice to the heat and continue cooking. Add the whiskey and clarified butter (ghee).
Let the jam bubble gently until the sauce thickens. Check with a drop of jam on a cold plate if it is ready. If it freezes, it is ready.
Pour the jam into clean, dry and warm jars. While it is still hot, seal the jars. Let cool upside down.