Hazelnut "Miracle" Cake

Why I Love This Recipe
I have no idea why it's called Miracle cake, and have no idea where I copied the recipe from, probably from my aunt and probably long time ago. But I'm glad I have, because this weekend I used this recipe for my daughter's birthday cake and I really liked it, but then hazelnuts are my favourite nuts, especially when toasted, because their flavour becomes more intense. And for this cake I toasted them in the oven for 15 - 20 minutes, at 200°C.
I cut the baked cake in two horizontally and filled it with hazelnut buttercream, and then covered it with MMF.
Ingredients You'll Need
4 eggs
250 g sugar (I actually reduced the original 300 to 250, but might even go down to 200)
200 g flour
100 g ground hazelnuts
2 teaspoons baking powder
1 tblspoon cornstarch
1 lemon juice
Directions
Separate the egg yolks from the whites.
Beat the egg whites with a pinch of salt until soft peaks form and set aside.
Beat the egg yolks with sugar until creamy, add 10 tblspoons of cold water (one at a time).
With a woden spoon fold in the dry ingredients - flour and cornstarch sifted together with baking powder, and hazelnuts.
In the end add lemon juice, always mixing gently with a wooden spoon.
Bake in a greased and floured cake form for about 30-35 minutes in an oven preheated to 180°C. Do not open the oven during the first 25 minutes or the cake might "sink" in the middle. I always do the toothpick check. before taking the cake out of the oven.
Let the cake cool completely before decorating it with your favourite buttercream or other filling/frosting.