Step 1Sift together flour, cocoa, baking soda and salt into large bowl.
Step 2 In another bowl, whisk together applesauce, sugar, oil, eggs and vanilla until blended. Make a well in dry ingredients. Pour in applesauce mixture and stir just until incorporated. Spread batter into greased 13x9-inch pan and smooth top. Sprinkle evenly with walnuts and chocolate chips.
Step 3Bake at 350 degrees until toothpick inserted in center comes out clean, 30 to 35 minutes. Let cool at least 15 minutes before cutting and serving.