Beat the egg whites into a light snow, but not stiff, and gradually add the sugar. Add the sifted flour and soft butter spoon by spoon. Mix to a homogeneous mixture. Cover a large oven dish (I use a square tray) with baking paper and gently grease it.
With a spoon spread the mixture into flat biscuits, about 4″ (10 cm) in diameter, but it can be more or less. Optionally, you can get creative and pull the ends a bit to make the biscuits look like little suns. Sprinkle with coconut and put to bake in a preheated 356°F (180°C) oven for 4-5 minutes.
Once ready, remove, leave for 30-40 seconds and place each flat biscuit on an inverted cup, then push it to the cup's walls to take on the form of the cup. Leave to cool.