Peel and quarter the pineapple, remove the center piece. Wash the cherries, remove the stalk and stone them. Cut the pineapple pulp into small pieces and puree with 2/3 of the cherries with the cutting stick / or food processor. Mix 2 tablespoons of sugar with the gelling agent, fruits and fruit puree. Bring everything to the boil while stirring and let simmer for another 4 minutes. Pour hot into clean jars and close.