My Mum is an amazing forager and maker of all things natural and yummy - the apples and thyme grow on the property and Dad and her picked a huge amount of blackberries around St Germain Nature Reserve...here is the recipe...
3lb blackberries - washed
1 1/2 lb Bramley apples - roughly chopped, core and all. Don't peel
1 pint water
2 or 3 large sprigs of thyme
Put all above into pan, bring to boil and simmer for an hour. Put into jelly bag suspended above a bowl and leave overnight.
Next day measure liquid and match with same amount of warmed sugar. Over medium heat ensure sugar has dissolved completely and then boil vigorously for about 10 minutes. Test as for jam. Once setting point is reached, test to see if the thyme flavour is to your taste, if not add thyme leaves to taste.
Sterilize jars and bottle as soon as possible as it sets really fast!
Good with pork, chicken, duck and turkey, but also works with lamb. Keeps well, I am just finishing some I made in 2013 and it's fine.