Preheat the oven to 360F.

First, chop the walnuts and dates, place both in a bowl, add flour, and mix it all together.

This cake has three layers. In my KitchenAid, I can mix 10 egg whites with 1.5 cups of sugar  (which is enough for 2 layers) at once, so I do that first. Then, transfer the mixture to a big bowl and beat the remaining five egg whites and remaining sugar. Put both mixtures together. Then fold in the dry ingredients.

Line 3 pans (10″ round) lined with parchment paper.

Bake for 25 minutes.

Filling:

Mix the yolks and cornstarch with 1-1/2 cups milk. Put the remaining 2-1/2 cups milk in a pot, add orange zest and juice, sugar, vanilla and bring it to boil.  Lower the heat, pour in the egg yolk mixture, and cook for about 2-3 minutes or until it is thick. Cover with a plastic wrap and leave to cool.

The butter needs to be softened and mixed in a separate bowl.

When the cooked filling is completely cooled, transfer to a mixer bowl, start beating until smooth; gradually add butter; mix until blended well.

Chill in the refrigerator until firm enough and easy to spread onto the cake layers. Reserve about 1.5 cups to put on top of the cake and on the sides and use the rest between the layers.

Decorate with whipping cream or icing of your choice.