Directions: In a mixing bowl, combine flour, sugar, cinnamon, salt, baking powder and baking soda. Combine oil and eggs; add to dry ingredients and mix well. Add zucchini; stir until thoroughly combined. Fold in walnuts if desired. Pour into a greased 13-in. x 9-in. x 2-in. baking pan. Bake at 350 degrees for 35-40 minutes or until a toothpick inserted near the center comes out clean. Cool. For frosting, in a small mixing bowl, beat cream cheese, butter, milk and vanilla until smooth. Add confectioner's sugar and mix well. Frost cake. Sprinkle with nuts if desired. Store in the refrigerator.