A foaming method is any method in which eggs are whipped or beaten to incorporate air before they are mixed into a batter. The air incorporated into the eggs creates a light and airy batter and helps to leaven the final baked item. The air trapped in the eggs will form pockets that, during baking, will expand and cause the product to rise.
Egg foams are very delicate, so it is important that all ingredients and equipment be assembled and receive any preliminary treatment before you begin to mix the ingredients; this will help to assure that the foaming process proceeds as quickly as possible, thus preventing any loss of volume in the batter.