1Place a small saucer in the freezer to chill. In a medium, heavy saucepan or pot, stir together the strawberries, sugar, and lemon juice. Bring to a boil over medium-high heat, stirring to dissolve the sugar. Reduce the heat to medium and simmer, uncovered, stirring occasionally, until the berries become very tender and the juices thicken, about 20 minutes. Use a potato masher to mash up the berries slightly.
2To test the jam and see if it is ready, spoon a little jam onto the frozen saucer. Let it stand for about 15 seconds. If the liquid thickens to a jam-like consistency, it’s ready. If not, continue to cook for another minute or two.
3To store the jam, let it cool completely. Transfer to clean airtight containers and store in the refrigerator for up to 1 month or in the freezer for up to 3 months. You can also can the jam according to our canning instructions.