1Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9 inch pans. Combine the graham cracker crumbs, brown sugar, walnuts and butter. Divide mixture evenly between the prepared pans. Set aside.
2In a medium bowl, mix together the cake mix, water, orange juice and oil until blended. Beat in the eggs, one at a time, then stir in the orange zest. Pour the mixture evenly over the crunch layer in the pans.
3Bake in the preheated oven for 30 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool for 10 minutes, then invert onto a wire rack and cool completely before frosting. Frost (crunch side up) between layers, on top and sides. Arrange orange sections on top, then refrigerate.
4To make the frosting: In a medium bowl, beat the vanilla frosting until light and fluffy, then mix in the whipped topping. Stir in the orange and lemon zest. Use frosting on completely cooled cake layers.
Footnotes
Tip
Parchment can be used for easier cleanup/removal from the pan.