In a small saucepan, stir together all ingredients. Bring to a boil over medium-high heat. Cook, stirring frequently, for 5 minutes. Reduce heat to medium, and cook, stirring frequently and mashing berries, until mixture thickens, starts to bunch in pan, and falls off a spatula in thick, jellied clumps, 15 to 20 minutes. (See PRO TIP.) (Stovetops vary; adjust heat as needed to prevent jam from burning.) Remove from heat; transfer to a small bowl, and let cool completely before using. (Jam will set up very thick, almost like fruit leather. If it becomes too thick to spread on scones, gently microwave on high in 10-second intervals, stirring between each, until it is smooth enough to spread.)