500ggranny smith or brambly apples(350g peeled & cored weight)
450ggranulated sugar
1lemon (juice of)
½vanilla pod (seeds)
Instructions
Wash blackberries gently in a large bowl filled with cold water. Drain them over the sieve or colander and let them dry a bit. Peel and core all the apples. and cut them into small cubes.
Put blackberries, apples, sugar, lemon juice and seeds scraped out of half a vanilla pod in a large stainless steel pan (preferably the one with quite a thick bottom) or a special preserving pan if you have one.
Place the pan on a medium heat and stir gently. The fruit will release their juices and will start bubbling away. You will need to turn the heat up and and bring the mixture to quite a rapid boil. You want the fruit to disintegrate completely. It's ok to give it a prod with a wooden spoon now and again to help it on its way.
I used granny smith apples here so it took a while for the fruit to soften but if you use bramleys, it shouldn't take as long. For my jam with listed quantities it took exactly 55 minutes to reach the setting point. To check whether your jam is ready you can use special jam thermometer or the "wrinkle test" where you place small plate into the freezer and when you see that your fruit looks more mushy and reduced you put a small amount of jam onto the very cold plate and put it in the fridge for a couple of minutes. If the jam "wrinkles" as you push it with your finger that means it's ready. If it doesn't then let it bubble few more minutes. You might have to make quite a few of these checks unless of course you are using thermometer.