This recipe works for most types of fruit and does not require the use of commercial pectin.
fresh cherries (pitted and chopped)
2 lemons (juiced and zested)
Cook chopped cherries for twenty minutes in a large, heavy-bottomed, non-reactive sauce pan with zest and juice from 2 lemons
After cherries are cooked measure the mixture and add 3/4ths that amount of sugar to the mixture.
Cook over high heat until mixture froths (forming natural pectin), once the mixture begins to bubble like syrup remove from heat and test a small amount in a small glass dish in the freezer.
Once mixture reached desired consistency, ladle into jam jars which have been sterilized. Top with sterilized flats and rings, and process in a hot water bath according to Ball Blue Book instructions.