In a large saucepan, combine 4 cups of dried apples and water. Bring to a boil, and let simmer over medium-low heat for 30 minutes, or until apples are very soft. Mash the apples slightly, and stir in the sugar. Set aside to cool.
Preheat the oven to 400 degrees F (200 degrees C).
In a large bowl, cream together the shortening and 1 1/4 cups sugar until light and fluffy. Stir in the buttermilk, baking soda, baking powder, salt and ginger. Mix in the flour about 1 cup at a time to form a stiff dough. Divide dough into 5 equal portions. Pat each portion of the dough into a 9 inch circle on greased cookie sheets.
Bake for 6 to 8 minutes in the preheated oven, or until edges are golden. Carefully remove layers to a cooling rack.
Stack the layers onto a serving plate, spreading about 3/4 cup of the apple filling between each layer. Spread the rest of the filling over the top layer, and arrange dried apple slices on top for garnish. Let stand overnight before serving.