Combine 2 pounds plum tomatoes, cored and cut into ½-inch pieces; 1¼ cups sugar; ¾ cup red wine vinegar; ¼ cup fish sauce; 6 minced garlic cloves; 1 minced large jalapeño; 1 tablespoon grated ginger, and 2 star anise pods in 12-inch skillet.
Bring to boil over high heat.
Reduce heat to medium-high and simmer, stirring often, until mixture is thickened and has darkened in color, 25 to 30 minutes.
Discard star anise.
Mash jam with potato masher to even consistency.
Continue to simmer until silicone spatula or wooden spoon leaves distinct trail when dragged across bottom of skillet, 5 to 10 minutes longer.
Transfer jam to two 1-cup jars and let cool completely.
Cover and refrigerate for at least 24 hours before serving. (Jam can be refrigerated for up to 3 weeks.)
