Preheat oven to 350°F and prepare 3 8-inch cake pans.
Sift all the dry ingredients (except espresso powder) into a large bowl and stir together.
Whisk all the wet ingredients (except hot water) together, then pour into the dry ingredients and whisk everything until smooth and free from lumps.
Mix the espresso powder into the hot water and then pour it into the batter and whisk to combine.
Pour evenly into cake pans and bake for 25 minutes or until a skewer inserted comes out clean.
Make the Chocolate Ganache
Chop the chocolate into small pieces and put it into a bowl.
Heat the cream in a saucepan over a medium-low heat until just before boiling, remove from the heat and pour over the chopped chocolate.
Stir the chocolate and cream together until all the chocolate has melted and the mixture is thick and glossy. Allow to cool before using.
Assemble and Decorate
Cut the tops off the cakes so they are flat.
Cut each cake in half so you have 6 thin layers.
Stack the cakes one by one with an even layer of cooled chocolate ganache spread in between each layer.
Cover the top and sides with chocolate ganache. Spread messily for a Matilda style look, or smooth out and add a chocolate drip for a more elegant finish.