Making zucchini cake requires ground cinnamon, vanilla and grated zucchini in addition to the basic cake ingredients of flour, sugar, salt, baking soda or baking powder, and eggs. The frosting requires cream cheese, butter, confectioner's sugar and vanilla. Some recipes add walnuts to the cake and milk to the frosting.
To make a 9-inch zucchini cake with three layers, mix 3 cups flour, 3 cups sugar, 1 teaspoon salt, 1 teaspoon baking powder, 1 1/2 teaspoons baking soda and 2 1/2 teaspoons ground cinnamon. Separately, beat four eggs, 1 teaspoon vanilla and 1 1/2 cups vegetable oil, and pour the wet mixture into the flour mixture. Stir together the two mixtures, then add in 3 cups grated zucchini. If desired, fold in 1/2 cup chopped walnuts and pour the batter into three 9-inch pans that are lightly greased and floured. Bake the cake at 325 degrees Fahrenheit for about 25 minutes, then let it cool for 10 minutes before removing it from the pans.
To make the frosting to ice the zucchini cake, beat one 8-ounce package of softened cream cheese and 1/2 cup softened butter until smooth. Gradually mix in 2 cups confectioner's sugar, beating with each addition until smooth. Mix in 2 teaspoons vanilla. Frost each layer of cake, and stack the layers to form a three-layered cake. Frost the top and sides of the cake with the remaining frosting.