1). Preheat oven to 160 degrees Celsius. Grease two 8” round cake pans & line the bottoms with parchment paper and set aside.
2). To make the cake, use a stand-up mixer with the whisk attachment. Whisk the eggs and sugar on high speed for 15 minutes until fluffy and three times the volume.
3). In a medium-sized bowl, combine the flour, baking powder and salt. Add half of this to the egg mixture. Combine on medium speed. Add the other half of the dry mixture and mix again. You will find the batter has decreased in size again.
4). Last, add the milk, oil and vanilla and mix on low speed for the last time. Scrape the sides and bottom of the mixer to ensure all the ingredients are combined.
5). Pour the batter into the two prepared pans and bake for 25-30 minutes.
6). Meanwhile, make the custard filling. Heat the milk and vanilla on low heat. This will start to steam but will not boil. In a small bowl, combine the sugar, cornflour and salt. Set aside. In a medium bowl, whisk the whole eggs, egg yolk and sugar mixture until light and fluffy. This can be done using a whisk or a hand mixer. Add the sugar mixture to the egg mixture and whisk again.
7). Pour half of the steaming milk into the eggs, whisking constantly. Pour this mixture back into the pan with the milk mixture. Continue to whisk on low heat until thick – about 10 minutes. Set aside and cover the surface of the custard with cling film. Refrigerate for at least two hours.
8). Before you put your cake together, make the ganache either in a saucepan or in the microwave. Melt together the dark chocolate, cream, vanilla and salt. Be sure there are no lumps of chocolate remaining. Cool for five minutes.
9). Dollop the cooled custard onto the first layer of the cooled cake, avoiding the edges. Place the other layer of cake on top of the custard and gently press down onto it.
10). Pour the ganache over the top, allowing it to drip over the edges. Chill for at least an hour before enjoying. Keep this in the fridge.
