Cotton soft vanilla sponge cake, also known as Bánh Bông Lan in Vietnamese, is less sweet and lighter than the average American sponge cake. It contains less dairy and sugar than regular sponge cake, so it can be enjoyed in more quantities. The meringue portion of the cake requires a hand or stand mixer but otherwise only requires a large bowl and whisk to assemble. The cake is slowly baked in a water bath for 1.5 hours to ensure an even, gentle bake.