Chocolate Sandwich Cookies

Cream together sugar and shortening,

Add whole egg and two yolks and beat well,

Mix flour cocoa salt and soda and add alternately with sour milk,

Add hot water and mix,

Drop by spoonfuls onto greased cookie sheet and bake about 8 minutes at moderate oven about 350°F,

Cool on racks,

For filling beat reserved egg whites until slightly stiff,

Add powdered sugar vanilla milk and shortening and beat well,

Spread filling between pairs of cookies.