I made blackberry and pear jam on Saturday. Quite easy to do.
Here's the recipe:
1.5kg pears (weight after being peeled and cored)
Add the blackberries to the jam pan. Peel and core the pears then chop them and add to the pan.
Heat up and bring to boil. You are aiming to get the blackberry juice infused through the pear. Takes up to an hour of simmering after having been brought to the boil.
Then add the sugar, stirring constantly. Bring back to boil and keep the heat on til setting point is reached. Then put into warm jars.