Adapted from The Kitchen Sink and Eating Well

Makes 2 loaves

2 cups white whole-wheat flour
1/4 cup unsweetened cocoa, preferably Dutch-process
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
3 large eggs, lightly beaten
1 1/2 cups sugar
3/4 cup plain yogurt
1/4 cup canola oil
1 teaspoon vanilla extract
1 ounce bittersweet chocolate, melted
2 cups grated zucchini, from 1 large zucchini
1/2 cup dried cranberries (optional)

Preheat oven to 325°F. Coat two 8"x4" loaf pans with cooking spray. (I also lined the bottoms with parchment, although it probably wasn't necessary.)

Whisk flour, cocoa, baking powder, baking soda, and salt in a large bowl.

Whisk eggs, sugar, yogurt, oil, vanilla and melted chocolate in another large bowl until blended. Add to the dry ingredients and stir with a rubber spatula until just combined. Fold in zucchini and dried cranberries. Spoon the batter into the prepared pans, smoothing the tops.

Bake the loaves for 55 to 60 minutes, or until a skewer inserted in the center comes out clean. Let cool in pans on a wire rack for 10 minutes. Invert onto rack and cool completely.