Classic combination of chocolate and vanilla flavours with a zebra pattern twist! Soft and moist cake, filled with rich chocolate ganache and silky vanilla ermine buttercream.
Preheat your fan oven to 160°C (325°F). Grease and line with parchment paper three 6" round cake tins.
In a medium bowl sift together flour, baking powder and salt. Whisk until combined and set aside.
In a measuring jug combine sour cream, buttermilk and vanilla extract. These are your wet ingredients.
In a bowl of a stand mixer fitted with a paddle attachment, cream butter and sugar on a medium-high speed until pale and fluffy. (approx. 3 min) Stop the mixer and scrape down the bowl.
Turn the mixer to medium-low speed and add eggs one at a time - making sure it's fully incorporated after each addition. Stop the mixer and scrape down the bowl.
Add your dry and wet ingredients, alternating between one another, starting and finishing with dry ones. (3 additions of dry and 2 of wet ingredients)
Divide the batter in half and add cocoa powder in one to make a chocolate batter.
Divide the batters evenly among the 3 tins using spoons - putting a spoonful of one batter in the middle of the pan and then spoonful of the other batter on top of it. (Check the information in the post above)
Bake for 20-25 minutes or until skewer inserted in the middle comes out mostly clean.
Once they're done, let the cakes cool for 10-15 minutes on a wire rack before removing them from the pans to cool completely.
Vanilla Ermine Buttercream
In a small saucepan combine flour, sugar, salt and milk. Cook over medium-high heat, stirring constantly with a whisk until it thickens.
Once it's done, put a cling film over it touching the surface to prevent "skin" forming and let it cool to room temperature. This is your pudding base. You can do this in a fridge, but before using it let it come to room temperature.
Using a stand mixer fitted with the paddle attachment, beat the butter for 5 minutes until it's pale and fluffy. Then add spoonful by spoonful of previously made pudding. Mix until it's all nicely incorporated and with no lumps. Add the vanilla extract and beat for another 30 seconds.
Dark Chocolate Ganache Filling
Place finely chopped chocolate in a bowl. Bring heavy cream just barely to a simmer and pour over chopped chocolate. Cover it with a plate and leave it 1-2 minutes. Stir with a spatula until combined and smooth.
Cover in cling film and put it in a fridge for an hour or until it thickens to spreadable consistency.
Chocolate Ganache Drip
Place finely chopped chocolate in a bowl. Bring heavy cream just barely to a simmer and pour over chopped chocolate. Cover it with a plate and leave it 1-2 minutes. Stir with a spatula until combined and smooth. Make it 10 minutes before pouring over the chilled cake so it has time to cool and thicken a bit.
Assembly
Using a cake leveler or a long serrated knife level the tops of your cakes if needed.
In the middle of your cake board or a serving plate put some buttercream to stop the cake from moving around.
Spread a nice layer of buttercream on top of the first layer and pipe a border around the outside to hold the ganache in. Repeat with the next layer.
Place final layer on top, upside down, and do a thin crumb coat on the cake. Chill for 20-30 minutes in the fridge before final decorating.
Use the leftover ganache filling to make a chocolate buttercream, mixing it with some vanilla buttercream. If it's too loose, put it in the fridge to thicken a bit.
Place both of your buttercreams in piping bags. For a vanilla buttercream I used a Wilton 1A tip and for a chocolate buttercream I used a Wilton #12 tip. But you do you. :)
Place the chilled cake on a turntable and alternately put the stripes of buttercream on the cake. Once you're done, fill the top with vanilla buttercream and smooth the sides using a cake scraper.
Every time you use a cake scraper be sure to get rid of the buttercream that you've scraped down so you don't mess up the stripes.
Chill the cake for a half an hour to an hour before putting the chocolate drip on top. It has to be cold so the drip doesn't go all the way down.
Notes
If you don't have a stand mixer, you can use a hand mixer.
Not all ovens are the same. I suggest to check the cakes at 18 min mark and then adjust the baking time accordingly. Get to know your oven! :)
If you still don't own one, I advise you to buy a kitchen scale - they're cheap and easy to use, and always guarantee the same results in baking!
Cake is best eaten at room temperature. You can keep it in a fridge, wrapped in cling film, but take it out of it at least half an hour before serving. :)