A five-egg iteration.
From the box of A.D. from Lutz, Florida, by way of Pennsylvania in the 1940s, and originating in Ohio in the 1920s.
White Cake
5 egg whites
2 cups sugar
3 cups flour
3/4 cup butter
3/4 cup milk
2 tsp. baking powder
1 tsp. flavor [vanilla]
In a large bowl, cream butter and sugar well. Add milk, then flour and baking powder and flavor. Mix well. Add egg whites well beaten.
Bake in layers.