Cakes are usually made by either the creaming method or the all-in-one method. In all-in-one method, all dry and liquid ingredients are mixed together at once and the fat (butter) is added later on and mixed together until the dry ingredients are well coated with fat. This method eschews any actual bubble-making and thus usually call for a good deal of baking powder than recipes using creaming method.
Having said that, in this recipe I did not use any baking powder and flour and to give a lighter finish, I separately take out eggs white and made meringue and added to the batter before adding the butter.
This cake is a tradition of North Italy Genova district.