1. Preheat the oven to 350°F (180°F). Line two 8 inches (20m) springform tins and grease lightly.  Set aside. Wash the zucchini and shred (not too fine). Set aside.

 

2. Add the coconut flour, cocoa powder, xylitol (erythritol), espresso powder, baking powder, baking soda, and salt to a bowl and mix until well combined. Add the eggs, oil, and vanilla extract to a large bowl and whisk to combine. Add the dry ingredients and mix them in. Add the shredded zucchini and fold in. Divide the dough between the two baking tins and smooth out the top. Bake for 25-35 minutes or until a wooden skewer inserted into the center comes out clean. Take out of the oven and let cool down in the tins for some time, then remove carefully and let cool down completely on a wire rack.

 

3. For the buttercream add the egg whites and xylitol (erythritol) to a heatproof bowl and place on a pot with simmering water. Mix and heat up until the mixture reaches a temperature of 160°F (71°C). Transfer to the bowl of a stand mixer and whisk on high speed for about 5-6 minutes until light and fluffy – the bowl should have room temperature. Gradually add the butter in small pieces and mix it in. Add the vanilla extract and cocoa powder and mix in – start slow and speed up so you do not end up with a cocoa cloud. Whisk another 2-3 minutes until you get a smooth chocolate buttercream. If the cream seems too stiff or still a bit grainy add some heavy cream and mix in.

 

4. To assemble the cake place one cake layer on a serving plate. Add some buttercream on top and spread evenly. Place the second cake layer on top and press down a bit. Cover the complete cake with the remaining buttercream – the surface does not have to be smooth, make some swirls here and there to give it some structure. Place in the fridge for at least 30 minutes before serving.