So after searching for a natural sweetener based jam and failing to find one I have made my own.

I am lucky or unlucky enough, depending on your point of view to have blackberry bushes on my fences so I took the opportunity to pick a 1 kg/2.2 lbs to make jam.

Make sure you have clean jars ready to go.

Ingredients 

1kg/2.2lbs of blackberries

150ml water

Juice of 1 lemon

12 sheets of gelatine

3/4 cup of erythritol (it acts as a preservative like sugar)

Method

Wash berries and remove any stems

Put berries, lemon juice and sweetener into a large saucepan with 150ml of water.

Bring to boil.

Place gelatine sheets in cold water for 3-5 minutes. Then drain water and squeeze.

Add gelatine to berries and simmer for 5-7 minutes.

Pour into jars. Seal jars and place in fridge to set. Store in fridge.