How to make
Wash the cherries abundantly with cold water.
Remove the stems and pits using a special device for removing pits.
Put the prepared black cherries in the pot in which we will cook the cherry jam, adding half a vanilla pod and cover with sugar.
We let them stay like that overnight so that they can release their juice.
Add the water and put the pot on moderately high heat.
When the sugar melts and the jam begins to boil, foam forms on the surface of the vessel. Using a slotted spoon, we remove it.
Boil the jam to the desired thickness.
At the end of cooking, add the citric acid.
We wash two jars, because for this amount, that's how many are made, we dry them and fill them with black cherry jam.
We close with the lids while it is still warm and turn them over.
We leave it like this until the jam cools down completely and then put it away.