Ingredients
750g pitted cherries, fresh or frozen 
1 lemon, juice, zest and pips 
750ml water 
400g granulated sugar  
350g jam/gelling sugar with added pectin  

Method
First take 2 saucers and put into the freezer. 

Take your lemon and with a peeler, peel off strips of the rind trying to avoid taking too much of the bitter white pith.  Into a heavy based large pan put the cherries, lemon juice, lemon rind and in a little muslin bag, put all of the pips and also put this into the pot.  Add the water and put on a medium heat and cook for roughly 20 minutes until the liquid is simmering and the cherries soft. 

Meanwhile wash the jam jars in hot soapy water and put into a 180c oven. 

Add the sugars to the pan and stir until completely dissolved. Bring to the boil and boil rapidly for roughly 20 minutes.   You do need to be careful that the hot molten liquid does not bubble up and hit you because it will really burn.  After 20 minutes take 1 of your saucers and 1 tsp of the jam and put it on the saucer and leave for a minute or so.  Take your finger and push it against the jam, if it wrinkles when you push it with your finger, then it is ready to use. If not, cook for an additional 5 minutes and try again. 

Carefully take the jars and very carefully pour the jam into the hot jars.  You need both the jars and the jam need to be at the same temperature otherwise the jars could crack.