Preheat oven to 325°F. Butter an 8-inch round cake pan. Place one-third of the apple slices in pan. Whisk sugar, butter, and egg together in a bowl. Stir in one-third of the apple slices. Sift flour, baking soda, cinnamon, nutmeg, all-spice and salt together. Add egg mixture and apple sauce along with raisins, stirring until just blended. Pour into prepared cake pan and smooth top. Arrange remaining apple slices in a pattern on top and press into batter. Sprinkle with cinnamon and sugar mixture. Bake until golden and springs to the touch, about 50 minutes. Let cake stand on a wire rack for 10 minutes, then turn out and let cool completely, about 2 hours. Dust with powdered sugar and cut into wedges to serve.