Ingredients

2 cups peeled and grated zucchini (2 to 4 zucchini)
1¼ cups all-purpose flour
1/4 cup Dutch-process cocoa powder (like King Arthur Flour's Black Cocoa)
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon instant espresso powder
1 teaspoon salt

1 large egg
1/2 cup light brown sugar, packed
1/4 cup granulated sugar
4 tablespoons unsalted butter, melted
1/4 cup canola oil
1 tablespoon distilled white vinegar
1 teaspoon vanilla bean paste or vanilla extract

Preparation

Preheat the oven to 350°F. Spray two 7-by-3½-inch loaf pans with nonstick cooking spray.

Put the grated zucchini in a sieve and allow any excess moisture to drain.

In a large mixing bowl, whisk together the flour, cocoa powder, baking powder, baking soda, espresso powder, and salt for 30 seconds to evenly distribute the leavening.

In the bowl of a food processor, pulse together the zucchini, egg, both sugars, the melted butter, oil, vinegar, and vanilla until combined. Add the flour mixture and pulse until a homogeneous batter forms. Divide the batter evenly between the prepared pans. Bake until a toothpick inserted in the center comes out mostly clean with a few moist crumbs attached, 30 to 35 minutes.

Gluten-free version

Reduce the zucchini to 1½ cups.
Replace the flour with 1 cup finely milled brown rice flour, 1/4 cup sweet white sorghum flour and 1 teaspoon xanthan gum.
Increase the eggs to 2.
Replace the oil with 4 tablespoons unsalted butter to make 1/2 cup butter total. Melt the butter and let cool slightly.

Vegan version

Replace the egg with 1 large eggs worth of flaxseed meal mixed with water (see recipe below).
Replace the butter with another 1/4 cup canola oil to make 1/2 cup canola oil total.
Ener-G-egg replacer: 1½ teaspoons egg replacer powder stirred or whisked thoroughly with 2 tablespoons warm water = 1 large egg

This mixture is often lumpy, so it’s worth running the finished mixture through a fine sieve before using. You can use this mixture immediately. This egg replacer is wonderful when more than one egg is called for. It is relatively flavorless and contains a measure of leavening (it’s gluten free as well). It acts as both a leavening agent and a binding agent.

Healthier version

Replace the flour with ¼ cup (40 grams) Sprouted Super Flour and 1 cup organic whole-wheat pastry flour.
Replace both sugars with 3/4 cup organic granulated palm sugar.
Replace the butter with 1/4 cup pureed black beans (from a can of cooked organic black beans, pureed in a blender or food processor).
Replace the oil with 1/4 cup organic grapeseed oil.
Add 2 tablespoons orange juice to the wet ingredients.