Frozen-Berry Jam

In a medium saucepan, combine raspberries, sugar, lemon juice, and salt and bring to a boil over medium-high heat, stirring until sugar dissolves.

Cook, stirring often and mashing berries with the back of a spoon, until mixture thickens to a jam-like consistency, 6 to 8 minutes. Strain through a sieve, if desired, then transfer to a heatproof jar and let cool completely. Refrigerate up to 1 week or freeze up to 3 months.