Wash, stalk and stone the cherries. Weigh 1.3 kg cherries. Mix the cherries, lemon juice, jam sugar and kirsch well in a large pot and leave to stand for 3-4 hours. Bring jam to the boil and boil for about 10 minutes while stirring occasionally.
Dissolve the cocoa in the jam while stirring. (Skim off any foam that may have formed.) Roughly chop the chocolate and stir into the jam. Pour jam immediately into prepared twist-off jars. Place on the lid for approx. 5 minutes, turn over and allow to cool. Jam keeps for about 3 months
waiting time 3-4 hours