Have all the ingredients at room temperature.

Preheat the oven to 350°F.

Grease and flour a 9-by-3 inch cake pan.

Mix the flour, ground chocolate, baking powder, baking soda and salt in a mixing bowl and set aside.

In another mixing bowl beat the butter with an electric mixer for 1 minute on low speed.

Add the sugar, increase the speed and beat it for about 3-4 minutes until fluffy.

Add the oil and beat until incorporated.

Add one egg at time, beating for 1 minute each time until incorporated. Occasionally scrap down the sides of the bowl.

Add the vanilla extract.

When the mixture is creamy, add the flour chocolate mix alternating with the buttermilk, beginning and ending with the buttermilk.

Add the zucchini and mix.

Pour the batter in the previously prepared cake pan and bake it for 1 hour, until a toothpick inserted into the center of the cake comes out clean.

Transfer the pan to a wire rack and let it cool for 10 minutes.

Unmold the cake and let them completely cool down before dusting with the confectioner’s sugar.