In a large skillet, combine raspberries, sugar, lemon juice, and a pinch of salt. Cook over high, stirring, until sugar dissolves and mixture boils. Reduce to a rapid simmer and cook, stirring occasionally, until mixture thickens, 12 to 15 minutes. Transfer 3/4 cup jam to an airtight container. Using a fine-mesh sieve, strain remaining jam into container, pressing on solids. Discard seeds. Stir jam to combine: Let cool completely. Cover and refrigerate, up to 1 month.