Preparing the cake layers:
Beat the egg whites with the sugar (added in lots while beating) to hard snow.
Add the sifted flour, mixed with the coconut, in lots - stir carefully with a spatula with gradual motions from bottom to top.
Distribute the mixture into 4 baking sheets. It's best to cut off a sheet of baking paper, then trace a circle on it and divide up the batter into 4 parts. Lay out each starting from the middle to the edge of the circle and even going a little beyond the edges. Be sure to spread it out evenly everywhere because if it's thinner around the edges it'll break there. Do this for all of them and bake them all together if possible.
Bake at 311°F (155 °C) for 15-20 min. Check to see if it's ready by touching it with your hand, it needs to be springy. Take them out and remove the paper while still hot. Let them cool and trim down to size with a ring or the cake form you intend to bake in.
Preparing the buttercream:
Beat the softened butter until whitened. Add the condensed milk in lots while beating.
Enrich with coconut flakes and melted white chocolate. Divide the mixture into 3 parts.
Sticking the cake layers together:
Smear the cake layers with the buttercream and stick them together - place 1 with the top facing up and the others with their bottoms facing up.
Let it cool.
Preparing the Raffaello bonbons:
Mix together the water, butter and sugar, boil until thickened and pour in a trickle to the dry milk, while beating an egg beater.
Sift and add 2/3 of the coconut and the vanilla. Stir until homogeneous and cool (it forms a thick batter, so there's no need to strain).
Form balls, 2 tsp (10 g) each, and place 1 hazelnut in each.
Roll in the rest of the coconut and let cool.
Preparing the cream mixture for decoration:
Combine the confectionery cream and sugar and beat to a medium-hard cream.
Release the cake from the cake form - smooth it out on top and sides with the cream mixture.
Sprinkle with coconut flakes all over. Mark out 14 slices of cake.
Decorate each slice with a Raffaello bonbon.