It's best to pulverize the walnuts for this cake until they reach a sand-like consistency. This will serve as the walnut flour, which will hold everything together.
The egg whites and yolks are used separately for this cake, too. The beaten egg whites lift the cake, while the combined yolks and sugar create a moist texture.
Because this cake is so moist, be sure to line the cake pan with a baking sheet before baking and bake your cake on low so it doesn't fall apart or burn once you remove it.