Chocolate Zucchini Cake

Name: Chocolate Zucchini Cake
Ingredients: 3 large eggs; 1/2 cup buttermilk; 1 stick plus 1 tablespoon (9 tablespoons) unsalted butter, divided; 1 pound zucchini (1 large or 2 medium); 1/2 cup vegetable oil; 1 tablespoon vanilla extract; 2 cups all-purpose flour; 1 cup granulated sugar; 1/2 cup unsweetened natural cocoa powder; 1 1/2 teaspoons baking soda; 1 teaspoon ground cinnamon; 1 teaspoon kosher salt; 3/4 cup semi-sweet chocolate chips; 1 stick (8 tablespoons) unsalted butter; 2 cups powdered sugar; 1/3 cup milk; 1/4 cup unsweetened natural cocoa powder