Wash the cherries thoroughly, remove the pits, and halve them.

In a saucepan, combine the cherries, sugar, and lemon juice. Cook over medium heat, stirring frequently until the sugar dissolves.

Bring the mixture to a boil and add the pectin. Stir continuously for about 5 minutes until the mixture thickens.

Pour the hot jam into sterilized mason jars, leaving about ¼ inch of headspace. Seal the jars with lids.

Process the jars in a boiling water bath for 10 minutes to ensure they are sealed properly.

Remove the jars from the water bath and let them cool completely on a clean towel. Store in a cool, dark place.