Homemade Oven-Baked Plum Butter
·Prepare and macerate the plums
Wash the plums, remove the stones and cut them in half. Place them in a roasting tin, sprinkle with sugar, add the vinegar and stir everything together. Cover the tin and let the plums sit at room temperature overnight (12 to 24 hours) so they release plenty of juice.
Bake the plum butter with no stirring
The next day, put the roasting tin with the plums and their juice into an oven preheated to 150-180°C. Bake for approximately 1.5 to 2.5 hours, until the liquid has evaporated. Don't stir the plum butter at all while it bakes - just check on it visually from time to time.
Prepare the jars
While the plum butter is baking, get your jars and lids ready. Wash them thoroughly in hot water and rinse well. For extra cleanliness, you can also boil them or sterilise them in a hot oven for a few minutes. They need to be completely dry.
Flavour with spices and rum
Once the plums have turned dark and the juice has reduced to a syrupy consistency, take the tin out of the oven. Stir the ground cinnamon, crushed cloves and finally the rum straight into the hot fruit mixture. Blend for a smoother texture.
Jar and cool
Fill the prepared clean jars with the hot plum butter straight away. Screw the lids on tightly, turn the jars upside down and leave them in that position until completely cool. This naturally and reliably seals the jars.