Preheat your oven to 175 C, grease and line three 6 inch round cake pans and set aside.
Sift the flour, sugar, baking powder and salt into a medium-large bowl (If using a stand mixer, you may do so in the bowl of the mixer) you can also use a hand held mixer. Then add the freshly grated orange zest.
Now add the cubed room temperature butter into the sifted dry ingredients and start mixing at a low speed (use the paddle attachment), increase the speed after 10-15 seconds and mix for about 25-30 seconds until the flour looks like wet sand
Take a separate bowl, combine the eggs, freshly squeezed orange juice and vanilla and whisk until well combined.
Now add half of this mixture to your flour and butter, mix it on medium high speed for one minute. This step will build the structure of the cake. It is very important to make sure that you beat the mixture for at least one minute otherwise your cake will not have structure
After one minute, stop the mixer and add half of the remaining liquid and whip for 20-30 seconds, do the same with the last amount of liquid.
Once the batter looks smooth stop mixing and pour the batter evenly into the three pans and bake for roughly 25 minutes or until a skewer inserted in the middle comes out clean.
Let the cakes cool completely before assembling
Whip the room temperature butter on high speed using a stand mixer or hand held mixer for 3 minutes until fluffy
Add the sifted icing sugar in two stages, whipping for 3 minutes between each addition
Add the cooled coffee and whip for 2 minutes.
Assemble the cake:
Once the cake is cooled, remove each layer and level them off to make them straight.
Spread a generous layer of frosting on the first layer and add the second on top. Repeat the same step for this layer as well.
Cover the cake with a thin layer of frosting and refrigerate till the butter is hardened and then slather on more frosting to give the cake a finished look.
Add some chocolate ganache (optional). Let the cake cool in the refrigerator for 30 minutes at least before cutting and serving.