Preheat oven to 180°C. Place butter and sugar in a bowl. Using a wooden spoon, combine well. Add eggwhites, 1 at a time, stirring until smooth. Stir in flour and a pinch of salt until smooth.
Using an 8cm pastry cutter as a guide, trace 4 circles, 4cm apart, on to a sheet of baking paper. Flip paper over and place on a greased oven tray.
Using a metric measuring spoon, spoon a slightly rounded tsp of mixture on to each circle. Use the back of a spoon to spread batter to fill circle.
Bake for 6-7 minutes or until cookies begin to brown around edges. Working quickly, slide a spatula under each cookie to loosen, then place a message on top of each.
Fold hot biscuits in half to enclose, pressing edges together,then bend in half the other way, over the edge of a glass, to create crescent shapes.Hold for a few seconds. Place on a wire rack to cool.
Finally ,Repeat with remaining batter. Store in an airtight container for up to 5 days. Cook's tip: Baking paper can be reused up to four times; any more and cookies won't be as smooth.