This cake magically transforms in the oven into a three-layer cake! This cake is bound to draw admiring comments, not just for how it looks, but also for how it tastes.
You don’t have to make a sandwich cake – if you prefer, make individual brownie-type squares with it instead – but this cake goes beautifully with extra-thick or whipped cream and seasonal fruit.
Preheat your oven to 325 F/150 C fan/gas mark 3. Line an 8×8 inch baking dish with parchment or baking paper.
Separate the eggs and add the egg whites to the bowl of your mixer. Mix until egg whites are stiff and stand in peaks when the mixer is lifted out.
Place the egg whites in a bowl and set aside.
Add the egg yolks and icing sugar to a different bowl, and mix together until mixture becomes like a cream and is light pale yellow in color.
Add the Nutella, melted butter, vanilla extract, pinch of salt, cocoa powder and continue mixing for another minute until well incorporated.
With the mixer on low, start adding flour to the mixer, one tablespoon at a time, until all the flour has been incorporated into the mixture.
With the mixer still on low, slowly start adding the milk and beat until everything is well mixed together. The mixture should be very thin, almost like a crepe batter.
Start gently folding in the egg whites, a third at a time using a spatula. Repeat until all the egg whites have been folded in. They do not have to be completely mixed in, it's OK to still see foamy bits floating around the top of the batter. The mix with the folded egg whites in will look something like this:
Pour the batter into the prepared baking dish and bake for 40 to 70 minutes or until the top is browned. The cake should be firm to touch, and should not wiggle when you move the dish. Insert a skewer into the middle and check to see if it comes out clean. If it does, the cake is ready.
When the cake first comes out the oven, it will collapse and wrinkle slightly, like in the image below. That’s normal, so don’t panic!
Let it cool completely, then place in the fridge for at least 2 hours.
Now comes the moment of truth! Has your cake separated into layers? Sprinkle with icing sugar, cut it into slices and if you wish, sandwich together with cream and garnish with fruit.
The baking time could vary quite a lot depending on your oven, but start taking a look at around 40 minutes to see how things are going. Don’t take it out of the oven to check – just a quick look and gently shake the pan to see if the cake still wiggles when moved. If it does, it needs more time in the oven.