Portuguese Chocolate Mousse

• Break the dark chocolate into small pieces and cut the butter into cubes.

• Separate the egg whites from the yolks. Place the egg whites in a clean, dry bowl.

In a heatproof bowl, melt the dark chocolate and butter together using a double boiler method.

A "double boiler method" is a cooking technique where a heatproof bowl is placed on top of a pot of simmering water, allowing the contents of the bowl to be heated gently and evenly through steam, commonly used for melting delicate ingredients like chocolate without burning them; essentially, the bowl is "double boiled" by the heat transferred from the water below.

Stir until smooth and well combined. Let it cool slightly.

Add the egg yolks, one at a time, into the cooled chocolate mixture, stirring well after each addition.

• In a separate bowl, add a pinch of salt to the egg whites. Beat them using an electric mixer until they start to form soft peaks.

• Gradually add the sugar, continuing to beat until stiff peaks form and the mixture is glossy.

• Gently fold one-third of the beaten egg whites into the chocolate mixture to lighten it.

• Carefully fold in the remaining egg whites in two batches, ensuring you do not deflate the mixture.

• Spoon the mousse into individual serving glasses or bowls.

• Refrigerate for at least 4 hours, or overnight, until set.