Melt the butter in a pan over a low heat. Mix the caster sugar and flour in a bowl. Add the egg whites and the melted butter and stir to a smooth mixture. Allow to rest for 2 hours.
Immediately place over the base of 4 upturned tumblers and pull down to make inverted cups. They harden at once into tuiles, which you can slide off. If they go soggy they can be recrisped in a low oven.
© 1998 Alastair Little. All rights reserved.