Mix the water with the espresso and the cacao powder. Now mix this well and then bring it to a boil. Then turn off the heat and let it sit for at least 10 minutes.
After that mix the egg with the Greek yoghurt and the oil. Blend this till smooth and then set it aside for later.
Now also mix the flour with the sugar, the baking powder and the salt. Start mixing it in a stand mixer and then slowly add the yoghurt mixture.
Once it’s fully incorporated add the cacao mixture and mix it for a minute.
Then take a big baking tray and grease the sides and bottom with some soft butter. Now dust a thin layer of cacao powder on the butter and pour the batter on top. Make sure it’s level and then bake it at 180 °C for 10 minutes.
Then let it cool down for 5 minutes before covering it with another tray and letting it sit for at least 2 hours.
