Preheat oven to 400ºF.  Grease 8 inch round cake pan. Wash and hull strawberries, reserve 6 for garnishing. With potato masher or fork, mash berries lightly. Sprinkle with 1/2 cup sugar. Let stand while preparing cake. In large bowl, combine flour, 1 tablespoon sugar, baking powder and salt. With pastry blender, cut in shortening until coarse crumbs; add milk. With fork, mix just until mixture forms soft dough. Turn onto lightly floured surface. Knead 8 to 10 times. Pat dough evenly in prepared pan. Bake 15 to 20 minutes, until golden brown. Invert shortcake onto platter. With long knife carefully split hot cake horizontally. Spread both cut surfaces evenly with butter. Onto bottom half, spoon half of sweetened strawberries. Top with other half of cake. Spoon remaining strawberries on top. Mound whipping cream over strawberries. Garnish with 6 reserved strawberries.