Meanwhile, clean out the saucepan; add remaining blueberries, 5 tablespoons granulated sugar and 1 tablespoon water. Heat to boiling, and crush blueberries. Using the same procedure as with the strawberries, strain and return to pan with 1 tablespoon cornstarch and 1 tablespoon water that has been mixed together. Cook over low heat until thickened. Spoon blueberry mixture over blueberries.