Wash black cherries (or sour cherries) and remove the tails if any.
Carefully remove the stones with a sharp object to avoid crushing
the black cherries. Add sugar and mix. If cherries are used instead
of black cherries, less sugar can be used.
Pour in a non-stick pot and leave for 2-3 hours. Some juice will
collect in the pot. Excess juice should be removed prior to cooking.
It can be used as cherry-drink. Bring to boil over high heat,
removing the foam occasionally. Add vanilla essence, and cook over
high heat for about 30 minutes until the mix becomes very thick.
Leave the mix in the pot overnight. If the mix becomes watery, cook
again over high heat until it thickens.