This is a recipe for easy cherry jam without pectin.
Wash, pit, and cut cherries in half
In a pot or deep pan, mix cherries and lemon juice at low heat.
Use a potato masher to mash the cherries and cook until they soften, about 5 minutes.
Add the sugar to the pot and mix at low heat until the sugar is fully dissolved.
Turn up the heat to a low boil for about 10 minutes. Stir continuously so the sugar does not burn.
To check if the jam is ready to set, spoon a small amount of jam on your chilled plate. Place the plate back in the freezer for a few minutes. Now, touch the jam. If it is wrinkly and gel-like, you are good to go. If not, boil for a few more minutes and check again.
When the jam is ready, remove from heat then carefully pour into jars. If your jars were warming in the oven, then be sure to use an oven mitt or glove to hold the jars while you fill them. Also, make sure to put the lids on very tightly. Then, turn the jars upside down to while you cool in order to seal them.
Finally, let the jam cool for about 10 minutes and then place the jars in the refrigerator.