01 -
In a medium saucepan over medium heat, combine raspberries, granulated sugar, lemon juice, and cornstarch. Stir until sugar has completely dissolved.
02 -
Bring mixture to a boil, then reduce heat to medium-low. Simmer for 10-12 minutes, stirring occasionally. Gently mash any large berry pieces with your spoon as you stir. The mixture should thickly coat the back of a spoon (it will continue to thicken as it cools).
03 -
Remove from heat and allow jam to cool slightly in the pan. Transfer to storage jars and allow to cool completely before adding lids. Store for up to 1 year in freezer, or up to 3 weeks in the refrigerator.