In the top of a double boiler beat eggs and sugar over warm water until we obtain some foam in the surface. Remove from heat and then, once cold, keep beating to get a stable foam.
Mix the chocolate powder in melted butter and blend into the foamy mixture.
Grease with butter a 5 cm high baking pan and sprinkle with sugar. Pour batter to 2/3 of pan height. Cover generously with sugar glass and cook in preheated oven to 190ºC.
We can make also individual cakes in small round moulds.