Wash, stalk and stone the cherries. Weigh 500 g of flesh. Select the raspberries, mash them and pass through a sieve. Put raspberry puree and cherries in a pot and mash.
Stir in jam sugar. Chop the chocolate. Bring the fruit to the boil while stirring and boil over a high heat for at least 3 minutes. Stir in chocolate. Pour the jam into the prepared twist-off jars, place on the lid for 5 minutes, turn over and allow to cool.