1/2 cup unsalted butter, softened
1 cup granulated sugar
2 large eggs
2/3 cup unsweetened cocoa powder
1 teaspoon vanilla extract
1/4 teaspoon salt
2 teaspoons baking powder
2 cups coarsely grated zucchini
1 1/3 cups all-purpose flour
1/2 cup semi-sweet chocolate chips
1. Preheat oven to 350°F. Butter and flour an 8×5-inch loaf tin; set aside.
2. In a large bowl, cream together the butter and sugar until light and fluffy, then beat in the eggs one at a time until completely combined. Stir in the cocoa powder, vanilla extract, salt and baking powder. Fold in the grated zucchini, then add the flour and chocolate chips to the bowl. Stir until just combined.
3. Transfer the batter to the loaf tin and spread out using a spatula or the back of a spoon. Bake for 50 to 60 minutes until the cake has risen and a toothpick inserted into the center of the loaf comes out without batter on it (the toothpick might just have some melted chocolate on it from the chocolate chips).
4. Let the cake cool in the pan for 10 minutes before turning out onto a wire rack to finish cooling completely.
found on thekitchn.com