CHOCOLATE-WALNUT MOUSSE CAKE

Steps:

• Preheat the oven to 350 degrees. Butter the bottom and sides of an eight-inch springform pan.
• Scatter the walnuts on a baking sheet and place in the oven. Bake until lightly browned and crisp, stirring occasionally, about 10 minutes. Let cool. Set aside eight of the largest pieces for garnish. Chop the rest into small pieces.
• Put the chocolate squares and butter in a saucepan and set the saucepan in a skillet of simmering water. Keep the water at a simmer. Stir the chocolate and butter until the chocolate squares are melted.
• Whisk the egg yolks and sugar in a mixing bowl and beat until the mixture is light and lemon-colored.
• Add the chocolate mixture to the egg mixture, stirring to blend well.
• Beat the egg whites until stiff but not brittle. If the whites are too stiffly beaten, they will not fold in properly.
• Add half the egg whites to the chocolate mixture, and beat. Using a rubber spatula, fold in the remaining whites and the chopped walnut pieces.
• Pour three-quarters of the mixture into the prepared pan. Reserve the remaining chocolate mixture for the frosting.
• Place the pan in the oven and bake for 50 minutes to one hour. The cake is done when a knife, straw, toothpick or cake tester inserted in the center of the cake comes out clean.
• When the cake is done, transfer it to a rack. Let it stand about 10 minutes. Remove the rim from the springform pan. Cool the cake thoroughly.
• Spoon a portion of the reserved chocolate mixture around the sides of the cake, smoothing it over. Build it up slightly around the top of the cake. Add the remaining mixture to the top of the cake and smooth it over.
• Hold a small sieve over the cake and spoon the cocoa into it. Sprinkle it evenly over the top of the cake. Chill briefly.
• Add the confectioners' sugar to the sieve and sprinkle it over the cocoa. Decorate with the reserved walnuts and the violets.