Sift together the flour, sugar, salt, and baking powder.

Cut in the butter or shortening with a fork until the mixture resembles coarse crumbs.

Remove 1 cup of the crumb mixture and set aside.

To the remaining crumb mixture, add the beaten egg yolks and milk.

Beat the egg whites until stiff peaks form.

Gently fold the beaten egg whites into the batter.

Pour the batter into two well-greased 9 x 9 inch pans.

Sprinkle the reserved crumb topping evenly over the batter in both pans.

Bake in a preheated oven at 400F (200C) for about 45 minutes, or until golden brown.

Remove from oven and immediately sprinkle with melted butter and cinnamon.

Let cool slightly before cutting and serving.