Cake

1/2 cup (8 tablespoons) butter
1/2 cup vegetable oil
1 3/4 cups sugar
1 teaspoon vanilla extract
1 teaspoon baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
2 large eggs
1/2 cup sour cream, buttermilk, or yogurt
2 1/2 cups King Arthur Unbleached All-Purpose Flour
3/4 cup King Arthur All-Purpose Baking Cocoa or Dutch-process cocoa
2 teaspoons espresso powder, optional but tasty
3 cups shredded zucchini (about one 10" zucchini)*
1/2 cup chocolate chips
*Why the range in weights? Zucchini's weight varies a lot, depending on its moisture. To avoid having to make a decision about weight, consider measuring zucchini by volume.

Icing

1 cup bittersweet chocolate chips