Pre heat the oven (200ºC thermostat 6/7). In a saucepan, melt the butter.
In a bowl, mix the sugar, flour and ground almonds. Beat the egg whites until stiff and add them to the bowl.
Incorporate the melted butter to the mixture. Put the mixture in baking pans. Put them in the oven for 15-20min depending on the size of the baking pans.