How to cook
Mix the powdered sugar with the butter. Add the egg whites and flour. Knead a dough, divide it in 2.
To 1 part add the coffee, to the other - the vanilla. Roll out 2 sheets, put one atop the other and roll it up.
Cut 1/2″ (1.5 cm) thick slices with a sharp knife. Arrange them in a tray laid out with baking paper.
Bake 40 min. at 356°F (180°C) and sprinkle with powdered sugar.