Put the strawberries in a food processor and pulse until coarsely chopped. Transfer to a large saute pan along with the sugar, lemon juice, balsamic and salt. Bring to a boil over medium-high heat and cook, stirring frequently, until thickened, 8 to 9 minutes. Transfer the jam to a heat-resistant container and cool to room temperature. Cover and refrigerate for up to 10 days.