Chunky apple cake with cream cheese frosting

1. Stir together first 4 ingredients in a large bowl until blended. Combine flour and next 3 ingredients; add to butter mixture, stirring until blended. Stir in apple slices and 1 cup walnuts. Spread into a greased 13x9 inch pan. Bake at 350 for 45 minutes or until a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack. Spread with Cream Cheese Frosting; sprinkle with walnuts, if desired CREAM CHEESE FROSTING: 1-8 oz. pkg. cream cheese, softened 3 Tbsp. butter or margarine, softened 1 1/2 cups powdered sugar 1/8 tsp. salt 1 tsp. vanilla Beat cream cheese and butter at medium speed with an electric mixer until creamy. Gradually add sugar and salt beating until blended. Stir in vanilla.