Chocolate mousse (Le Cordon Bleu Classic French Cookbook)

mousse au chocolat

2 egg whites
1-1/2 tablespoons finely granulated sugar
63 grams semisweet chocolate (64% min. cocoa)
2 tablespoons butter
1 egg yolk

1. Beat the egg whites with the sugar until stiff. Set aside.
2. In the meantime, bring some water to a boil in the bottom of a double-boiler
3. Melt the chocolate over the boiling water. When most of the chocolate is melted, remove from the hot water. Add the butter and mix until melted. Add the egg yolk and mix.
4. Carefully fold the chocolate mixture into the egg whites.
5. Divide the mousse between individual serving bowls or place in a single bowl. Refrigerate well.

Yield: 2 to 3 servings.

http://www.hertzmann.com/articles/2002/brasseries/recipes/recipe_08.html