Covered at room temperature for up to 5 days
May be frozen
1 1/3 cups white whole-wheat flour
1 ½ cups sugar
1 cup dark unsweetened cocoa
1 ½ teaspoons baking powder
1 ½ teaspoons baking soda
½ teaspoon salt
½ cup orange juice (no pulp)
1/3 cup canola oil
½ teaspoon pure vanilla extract
2 large eggs
1/3 cup boiling water
¾ cup shredded zucchini (from about 6 ounces zucchini), unpeeled, shredded on the small holes of a box grater
1 ½ cups walnut halves, chopped into ½ inch pieces, and ¼ cup chopped walnuts separated out to sprinkle on top
Preheat the oven to 350ºF. Place paper cups in muffin tins for 17 muffins.
In a large bowl, mix together the flour, sugar, cocoa, baking powder, baking soda, and salt. Add the orange juice, oil, vanilla, eggs, and boiling water and first stir with a silicone spatula (so water does not splatter) and then use the mixer to mix for one minute, until everything is thoroughly combined, scraping down the bowl as needed. Add the shredded zucchini and mix in well to distribute. Add the walnuts and mix in.
Use a 1/3 cup measuring cup to scoop up batter and divide among the 18 cups, filling no more than ¾ full. Bake for 30 – 33 minutes, or until a skewer inserted comes out clean. Let cool for 10 minutes in the pan and then turn muffins out onto a rack to cool to room temperature. Store covered at room temperature for up to 5 days or freeze for up to three months.