Preheat your oven to 180 °C / 350F. Spray three 8-inch cake tins with oil spray and line the bottoms with baking paper.
To a large jug or bowl, add the milk, oil, coffee, and butter and whisk to combine.
To a separate bowl, add the flour, caster sugar cocoa powder, baking powder, bicarb soda and salt and use a whisk to combine.
Add the wet ingredients along with the eggs to the dry ingredients and mix to combine taking care to scrape down the bottom and sides of the bowl. Add the boiling water and mix to combine.
Divide the batter evenly amongst the three cake tins. Bake for 20 minutes or until a toothpick inserted into the center comes out clean. Allow the cakes to cool for 5 minutes once baked and turn over onto a cooling rack to cool to room temperature. Once cooled, wrap in plastic wrap and chill in the fridge for 4 hours or overnight.