In a medium saucepan, whisk together sugar and cornstarch. Whisk in 2 tablespoons water, lemon juice, and 1 cup blueberries. Bring to a boil over medium heat, stirring constantly. Cook until mixture thickens and some blueberries have burst, 5 to 8 minutes. Remove from heat, and stir in remaining 1⁄2 cup blueberries. Let cool completely. Cover and refrigerate for at least 30 minutes or up to overnight before serving.
Recipe by TeaTime Magazine at https://teatimemagazine.com/mini-ricotta-cheesecakes-with-blueberry-topping/