Difficulty: Intermediate
Melt the chocolate gently over low heat with 3 tablespoons of water. Remove from heat once fully melted.
Soften the butter with a spatula to a creamy ointment-like consistency, without heating it to preserve its rich flavor.
Separate the egg whites from the yolks. Incorporate the yolks one by one into the softened butter. Sift in the icing sugar if lumpy, then mix thoroughly.
Blend in the cooled melted chocolate and flavor with vanilla or coffee extract. Work the mixture until smooth. Cool completely, then gently fold in the stiffly beaten egg whites.
Pour into a buttered, ribbed mold. Refrigerate for about 10 hours.
For the custard: Pour boiling milk over the egg yolks and sugar, whisked together. Thicken over low heat, stirring constantly. Remove just before boiling, when it coats the spoon. Cool completely.
To unmold, briefly dip the mold in hot water. Invert onto a serving platter and surround with chilled custard.
Source: The Hundred Best Desserts by Larousse.
