ROTW- Orange Crunch Cake

I thought with oranges (all citrus) being in season right now that I would try something a little different. I have never had an orange cake before and this one seemed especially yummy. I will tell you that is cake did not disappoint. It was fantastic! Light, but full of flavor, the orange zest in the batter came alive in your mouth, there is not the slightest taste of bitterness . The "crunch" was so good you could just sprinkle it over ice cream or add it to yogurt. This is a perfectly sweetened, wonderful cake that you will be proud to take to any gathering. But, in order to make this a little lower in calories I did make some adjustments to the recipe but I did not take out anything you will miss all changes in bold). What a great recipe this week.You will find this weeks "Recipe of the Week" link at right, just click on it and it will take you to the full recipe for printingIngredients1 cup graham cracker crumbs1/2 cup brown sugar1/2 cup chopped walnuts 1/2 cup butter, softened (I just short of melted only 1/3 a cup) 1 (18.25 ounce) package yellow cake mix (I used white cake mix)1/2 cup water1/2 cup orange juice1/3 cup vegetable oil3 eggs (I used 3 egg whites only)2 tablespoons grated orange zest 1 (16 ounce) can prepared vanilla frosting (I only used 8 ounces)1 (8 ounce) container frozen whipped topping, thawed (I used 12 ounces)3 tablespoons grated orange zest1 teaspoon grated lemon zest1 (11 ounce) can mandarin oranges, drained