Easy homemade plum jam just tastes so much better than anything you can buy from the grocery store. This is perfect on a fresh bread roll, croissants, scones and the perfect filling in crepes and pancakes.
Add the sugar and the plums to a large thick-bottomed pot.
Slowly heat the fruit and the sugar and stir until all the sugar has been resolved.
Add the lemon juice
Now bring the fruit mixture to a rolling boil for about 20 minutes and then do a wrinkle test. (This is done by placing a small plate in the fridge for 15 minutes to cool down. Drop a teaspoon of jam on the plate and push the jam with your finger. If it stays in place and has a gel-like consistency, your jam is ready to bottle.)
If your jam is still runny cook for another 5 minutes and then test again.
When your jam is ready, add the vanilla just before bottling and, stir well.
Spoon the hot jam into warm jars. Without touching the inside of the lids screw onto the jars and flip upside down leaving them to cool down.
Scrape the bottom of the pot regularly with a wooden spoon to ensure that the jam does not burn.