Spread apples evenly in greased 9" square pan.Combine 1/2 cup sugar, cinnamon and coarsely chopped walnuts.
Sprinkle over apples.
Combine flour, 1 cup sugar, baking powder and salt, stir well and set aside.
Combine egg, half & half and butter.
Mix well. Add flour mixture, beating until smooth.
Pour over apples, sprinkle with finely chopped walnuts.
Bake at 325° for 1 hour.