1
Break the chocolate into pieces and add the butter and sugar. Melt all together in a pan over a water bath. Stir until the mixture is completely melted and smooth.
2
Remove from the heat and allow to cool. Stir the beaten egg yolks and flour into the cooled chocolate mixture.
3
In another bowl, whisk the egg whites until stiff and fold a third of them vigorously and quickly into the chocolate mixture. Slowly and with feeling fold in the rest of the snow.
4
Next, prepare a baking tray 25 centimetres in diameter and grease it with butter. Stuff it with the mixture and place it in an oven preheated to 170 degrees for about 45 minutes.