Chocolate Layer Cake with Homemade Dulce de Leche

When it's some one's birthday, I believe in going all-out with the birthday cake. Even if that "some one" just so happens to be me.



Chocolate Layer Cake with Homemade Dulce de Leche
slightly adapted from Delicous

For the Dule de Leche:
from Smitten Kitchen
1 litre full-cream milk
1/2 stick cinnamon
1/2 vanilla bean, scrape the seeds out and keep the pod
1 cup white sugar
1/4 teaspoon sea salt flakes
1/4 teaspoon baking soda dissolved in 2 teaspoons water

For the Cake:
230g dark chocolate
170g unsalted butter, room temperature
350g light brown sugar
3 eggs, separated
375g cake flour
1 1/2 teaspoons baking soda
1 1/2 teaspoons baking powder
500ml buttermilk
2 teaspoons vanilla extract

For the Chocolate Filling:
200g dark chocolate, chopped
225g unsalted butter, room temperature
250g icing sugar, sifted
1 tablespoon buttermilk
1 teaspoon vanilla extract

Toppings:
170g dark chooclate, chopped
100g hazelnuts, toasted and chopped

Make the Dulce de Leche:
Put the milk, cinnamon, vanilla (seeds and pod), sugar and salt into a 2 litre saucepan (no smaller, as the mixture will bubble up when you add the baking soda). Bring it to a simmer, stirring now and then. Remove the pan from the heat and add the baking soda mixture. Be careful here, this mixture will rise up in the pan and bubbly like crazy, then it will settle down again.

Return the pan to the heat and continue to cook at a lively simmer for about an hour, stirring occasionally to make sure it isn't sticking. You needn't be too watchful at this stage.

After about an hour, the milk mixture will start turning a lovely buff colour. You'll need to start keeping an eye on the mixture as it will start to thicken from now on. Stir the mixture every 5 minutes or so until it gets thicker. Watch it like a hawk. The dulce de leche is ready with it is thick and is a gorgeous bronze colour. Set aside to cool.

Make the Cake:
Preheat the oven to 170 degrees C. Grease two 21cm round cake pans and line them with baking paper.

Melt 230g of the dark chocolate in a heatproof bowl suspended over a pan of simmering water. Don't let the pan touch the water. Once melted, remove from the heat and set aside.

In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, about 5 minutes. Add the egg yolks one at a time, beating well after each addition. Add the melted chocolate and beat to combine.

In a large bowl, sift the flour, baking soda and baking powder and stir to combine. Pour the buttermilk into a jug, add the vanilla and mix. Add one-third of the flour mixture and one-third of the buttermilk mixture to the chocolate mixture and beat to combine. Repeat the process two more times until everything is incorporated.

Put the egg whites into a clean bowl and whisk until soft peaks form. Add 1 tablespoon to the cake batter and mix to loosen the mixture, then fold the remaining egg whites in.

Divide the batter evenly between the pans and bake for 40 minutes, until a skewer inserted into the centre of the cakes comes out clean.

Cool the cakes in the pans for 10 minutes and then turn them out into wire racks to cool completely.

Make the Chocolate Filling:
Melt dark chocolate in a heatproof bowl suspended over a pan of simmering water. Don't let the pan touch the water. Once melted, remove from the heat and set aside to cool slightly.

Beat the butter with electric beaters until smooth, add the icing sugar, buttermilk and vanilla. Beat again until fluffy. Add the chocolate and beat to combine. Put the final layer of cake on top.

Assemble the Cake:
Slice the cakes in half horizontally. Place on half of a cake onto a cake plate. Spread half of the chocolate filling on top. Put another half of cake on it and spread the Dulce de leche on top (you may not use all of it). Add another layer and spread with the remaining chocolate filling.

Top the Cake:
Melt the 170g of the dark chocolate in a heatproof bowl suspended over a pan of simmering water. Don't let the pan touch the water. Pour the melted chocolate over the top of the cake and sprinkle with the chopped toasted hazelnuts.