Prepare the syrup first, by adding the water, sugar, and cocoa powder into a saucepan. Bring to the boil until you see a foam form at the surface (very similar to Greek coffee). Turn off from the heat and set aside to cool down.
Pre-heat your oven to 160 ℃
In a separate bowl, add the eggs and sugar and with a hand mixer, mix until it is light a fluffy.
Add the vanilla, butter and orange zest to the bowl and give it a quick mix with a whisk.
In a separate bowl, add in your dry ingredients. The flour, cocoa powder, baking powder and salt. Then mix until all is evenly combined.
Now add the dry ingredients to the wet ingredients bowl, then mix.
Prepare your baking dish. The size I have used in 32x21cm. Butter the surface and add in the cake batter evenly spreading it out.
Place into the oven and bake for roughly 30 minutes.
Get a utensil you can use to poke the cake (I use a souvlaki stick). Then poke holes throughout the cake. This is so the syrup falls evenly throughout the cake.
Pour the cooled syrup over the hot cake and let it sit for 30 minutes to soak it all in.
In a small pot, prepare the ganache by adding the cream and bringing it to a boil. Turn off from the heat and add the hot cream to the chocolate. Mix thoroughly to melt it all together.
Pour the ganache over the chocolate cake and evenly spread it over the top.
Let the cake come to room temperature and then place inside the fridge for a couple of hours to set the ganache on top.
For best results, let the cake sit out of the fridge to come back to room temperature for at least 30 minutes before serving. Enjoy!