Good-Cooking - Zucchini Fudge Cake

Ingredients

• 1 cup butter or margarine, softened
• 2 1/2 cups granulated sugar
• 4 eggs
• 2 teaspoons vanilla extract
• 3 cups all-purpose flour
• 1/2 cup baking cocoa
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 3/4 teaspoon salt
• 1 cup buttermilk
• 3 cups shredded zucchini
• 3 1/2 cups prepared chocolate frosting