In a medium saucepan, combine the blueberries, sugar, lemon juice, and salt. Mash with a potato masher or wooden spoon until the berries have released their juices.
Cook over medium-high heat, stirring occasionally, until the mixture has thickened, 18 to 25 minutes. Transfer to containers/glass jars and refrigerate for up to 1 month or freeze for up to 1 year.
The recipe called for ½ cup of sugar, which is how I made it, however I like my jam to be a little sweeter. Next time I’d use more sugar, so feel free to add more to taste until it reaches your liking.
This recipe can also be made with two 10-ounce bags of frozen blueberries instead of fresh. Cook the frozen berries for 2 to 3 minutes before mashing, then reduce the total cooking time to 15 to 17 minutes.
Recipe by In Good Taste at http://ingoodtaste.kitchen/easy-homemade-blueberry-jam/