Prepare a water-bath canner, jars, lids, and bands.

Place frozen cherries into a large dutch oven and bring to a low boil.

Simmer on low for 15 minutes, until cherries breakdown.

Immersion blend cherries in the dutch oven until pureed smooth.

Over low heat add sugar and lemon juice and stir well to incorporate. Do not allow sugar to scorch on the bottom of the pan.

Add in vanilla and pectin. Stir continuously and bring to a boil to activate pectin. (Follow the instructions on your pectin as some activate differently than others.)

Test for gel (I use the frozen spoon method). Cherry jam does not need to be extremely thick.

Remove from heat and ladle into clean hot jars leaving 1/4" headspace. Wipe rims with a towel or paper towel and cover with lids and bands.

Water-bath can for 15 minutes or according to your altitude requirement.

Remove from canner and allow to rest on the counter 24 hours before checking seals or removing bands. Any jars that failed to seal properly refrigerate.

Store jars in a cool dark place for up to a year.