Wash and seed the cherries (drain the cherries from the glass and collect the juice)
Wash the lemon. Cut off half the peel very thinly. If necessary, remove the rest as a rasp and put aside covered. Squeeze the lemon. Mix starch with 2-3 tbsp. cherry juice. Boil up the rest of the cherry juice and lemon peel.
Stir in starch, add cherries. Boil up again while stirring. Season to taste with 2-3 tablespoons of sugar, sherry or port wine. Leave to cool slightly. Remove lemon peel. Fill the cherries into glasses and let them cool down
Whip the cream until stiff. Let vanillin sugar trickle in. Stir quark, 2-3 tbsp lemon juice and 2 tbsp sugar until smooth. Fold in the cream. Spray on the cherries or put it on top as a blob. Decorate with lemon shavings if desired.