Crust: Mix 1 cup flour, 2 tablespoons sugar and the salt. Cut in butter with pastry blender or fingers. Mix in vinegar. With fingers press on bottom and 1 inch up sides of 9-inch loose-bottom layer-cake pan. Filling: Mix remaining 2 tablespoons flour, 1 cup sugar and the cinnamon; combine with 2 cups blueberries. Turn out in pastry-lined pan. Bake in preheated 400 degree oven for 1 hour. Remove from oven; sprinkle with remaining 1 cup blueberries. Cool, then remove rim of pan. Sprinkle blueberries with confectioners' sugar or top with dollops of cream before serving.