Four layers of delicious and moist cake, alternating between rich chocolate cake and tender hazelnut cake, filled with amazing white chocolate hazelnut ganache filling and coated in silky vanilla buttercream. It’s a dream come true!
Using a food processor, blitz chopped, roasted and skinned hazelnuts for approx. 5 minutes until you get a nut butter of liquid consistency. Kind of like organic peanut butter. Do not add any water. Make sure you have a good quality, sharp food processor, otherwise it might take you a lot longer or it may never get to liquid state. Keep it in a jar until using. It needs to be room temperature.
For Chcolate Cake layers:
Preheat your fan oven to 160°C (325°F) or 175°C (350°F) if you're not using a fan oven. Grease and line with parchment paper two 6" round cake tins. Alternatively, you can use two 7" cake tins but the layers will be somewhat thinner.
In a medium bowl sift together flour, cocoa powder, baking powder and salt. Add sugars, whisk until combined and set aside.
In a small bowl or a measuring jug, whisk together eggs, vegetable oil, sour cream and vanilla extract. These are your wet ingredients.
In a small pot, bring your water to a boil or simmer, it's important that it's hot. Add the wet ingredients to dry ones, stir a little bit, it'll be somewhat dry. Then add the boiling water and whisk until combined. I usually add the water in two stages to minimize clumps forming.
Divide the batter evenly in two tins and bake for 23-25 minutes or until skewer inserted in the middle comes out with few moist crumbs. Do not overbake it.
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.
For Hazelnut Cake layers:
Preheat your fan oven to 160°C (325°F) or 175°C (350°F) if you're not using a fan oven. Grease and line with parchment paper two 6" round cake tins. Alternatively, you can use two 7" cake tins but the layers will be somewhat thinner.
In a medium bowl sift together flour, baking powder and salt. Whisk until combined and set aside.
In a measuring jug combine sour cream and vanilla extract. These are your wet ingredients.
In a bowl of a stand mixer fitted with a paddle attachment, cream butter, hazelnut butter and sugars 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 evenly among the tins and bake for 20-25 minutes or until skewer inserted in the middle comes out with few moist crumbs.
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.
Hazelnut White Chocolate Ganache Filling:
Place hazelnut butter and finely chopped chocolate in a medium sized 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. Alternatively, you can do this in a microwave in 30 sec intervals.
Cover it with cling film touching the surface and leave it overnight to cool and thicken. It should be a spreadable consistency. Just before using it, whip it with a hand mixer for a couple of minutes, until paler in colour and fluffy.
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 with cling film and leave it overnight or put it in a fridge for an hour until it thickens to spreadable consistency. When you’re ready to assemble the cake, whip it up using a hand mixer for a couple of minutes until paler in colour and fluffy.
Vanilla Buttercream Frosting:
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 vanilla extract mix until everything is combined.
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.
Place the first chocolate cake layer on a cake board or a serving plate. Using a small offset palette knife spread the white chocolate hazelnut filling over the cake. Top it with the hazelnut cake layer and repeat the process, only this time with dark chocolate ganache filling. Place your second chocolate cake layer on top, spread it with white chocolate hazelnut filling.
Place final (hazelnut) layer on top, upside down, and do a thin crumb coat on the cake with white chocolate ganache. Chill for 20-30 minutes in the fridge before final decorating.
Once cooled, frost and smooth the sides with vanilla buttercream. Using the back of your small offset palette knife, dab around to make snowy effect. Or do whatever design you wish for!
For instructions on how to make white chocolate drip, check out this recipe! :)
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 20 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.