Prepare 3, 8-inch circle cake baking pans. You can either grease and flour your pans, or use parchment paper to line the bottom of the pan. See tips!
Into a mixing bowl sift together the flour, sugar, cocoa, baking soda, baking powder and salt.
To the dry ingredients add the eggs, coffee, buttermilk, oil and vanilla, and mix on medium speed for about 2 minutes (I use the paddle attachment). Mix well.
Pour the batter evenly into your prepared pans. Gently tap the pans on the countertop to remove air bubbles.
Bake for 20 minutes, then rotate your pans. Bake for about 15 minutes more, or until a toothpick inserted in the centre of the cake comes out clean.
When done, let your pans cool on a wire rack for about 20 minutes, then remove cakes from the pans.
Chocolate Buttercream Icing:
Beat together the butter, icing sugar, cocoa powder, milk and vanilla until the icing is nice and fluffy. Make sure to scrape the bowl often.
Putting it all together:
Once the cakes have cooled you can frost them.
If the cakes have too much of a rounded top, you can trim the tops to make them more level.
To frost the cakes, place one cake down onto a cake plate, spread on frosting. Place another cake on top. Spread on more frosting. Add the last cake and use the remaining frosting to cover the cake. Note:don't be skimpy with the amount of frosting between the cake layers...refer to the pictures above to see how much frosting should be between them.