Ingredients

• 2 1/2 cups all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 2 1/2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 1 teaspoon salt
• 1 teaspoon ground cinnamon
• 3/4 cup butter
• 2 cups white sugar
• 3 eggs, beaten
• 2 teaspoons vanilla extract
• 1/2 cup milk
• 3 cups grated zucchini
• 1 tablespoon orange zest
• 1 cup chopped walnuts
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• 1 1/4 cups confectioners' sugar
• 1/4 cup orange juice
• 1 teaspoon vanilla extract