In a small bowl, combine berries and 2 tablespoons sugar; let stand for 30 minutes. Drain berries, reserving juice. If necessary, add water to the juice to measure 1/2 cup. In a small saucepan, combine cornstarch and juice. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Stir in berries and cinnamon. Pour into a 3-cup baking dish coated with cooking spray.
In a small bowl, combine the flour, baking powder, salt and remaining sugar. Cut in butter until mixture resembles coarse crumbs. Stir in milk just until moistened. Drop dough in four mounds onto hot fruit mixture. Bake at 375° for 15-20 minutes or until biscuits are golden brown. Serve with whipped cream or ice cream if desired.