Preheat oven to 350 degrees F (175 degrees C). Grease a 9x9 inch baking pan.
In a large mixing bowl, cream together the shortening, and sugar until smooth. Mix in 1 cup of flour. Spread into the bottom of the prepared pan. This is the crust.
Bake for 15 minutes in the preheated oven, until firm.
In a separate bowl, beat the eggs and brown sugar together until thick and pale. Add the brandy and mix well. Combine the remaining flour, baking powder and salt; stir into the egg mixture. Mix in apples and walnuts. Spread the filling over the hot crust.
Bake for 30 minutes in the preheated oven, or until filling is set. Cool completely before cutting into squares.