When I crave jam, I demand it be as simple as possible. Dextrose?! Pectin?! I don't really even know what those are! Why google things when you can just make your own stuff? The only ingredients here are cherries, honey, and a fine appreciation for stickin' to the basics.
You will need:
5 cups of fresh cherries
1/3 cup of local honey
1 of the lemons life gave you
A food processor
A medium to large saucepan
Step 1: Force The Elderly To Do You Work For You
I can't stress this step enough. Why would you bother pitting cherries, measuring 5 cups worth of them (halved not sliced and diced), and then puree them in the food processor if you have a happy old woman to subject to that experience instead?