Active Time

　　45 minutes

　　Total Time

　　3 1/2 hours

　　This recipe, adapted from The Viennese Pastry Cookbook: From Vienna with Love, by Lilly Joss Reich, requires a Rehrucken mold—a loaf pan with a rounded, ridged bottom.

　　

Ingredients

Makes 10 servings

　　

For cake

1/2 cup sugar plus additional for dusting

　　1 3/4 cups whole unblanched almonds (9 ounces), finely ground

　　3 ounces fine-quality bittersweet (not unsweetened) or semisweet chocolate, coarsely grated

　　Pinch of ground cloves

　　Pinch of ground cinnamon

　　Pinch of ground allspice

　　5 large egg yolks

　　2 teaspoons finely grated fresh lemon zest

　　4 large egg whites

　　1/2 teaspoon salt

　　

For chocolate icing

3 ounces fine-quality bittersweet or semisweet chocolate, chopped

　　3/4 stick (6 tablespoons) unsalted butter, cut into pieces

　　1/3 cup slivered blanched almonds

　　

Special Equipment

a 12-inch-long metal Rehrucken mold

　　

Make cake:

Step 1

Preheat oven to 350°. Butter mold and dust with sugar, knocking out excess.

　　

Step 2

Stir together ground almonds, chocolate, and spices in a bowl. Beat yolks with 1/4 cup sugar in another bowl with an electric mixer until thick and pale, then beat in zest.

　　

Step 3

Beat whites with salt with cleaned beaters in a large bowl until they just hold soft peaks. Gradually beat in remaining 1/4 cup sugar and beat until whites just hold stiff peaks.

　　

Step 4

Stir one third of whites into yolk mixture to lighten, then fold in remaining whites in 2 more batches. Fold in ground almond mixture.

　　

Step 5

Pour batter into mold and bake in middle of oven until golden and a tester comes out clean, about 45 minutes. Cool cake in mold on a rack 10 minutes, then invert onto rack and cool completely.

　　

Make icing:

Step 6

Melt chocolate with 1 tablespoon butter in a small heavy saucepan over very low heat, stirring. Remove from heat and add remaining 5 tablespoons butter, 1 tablespoon at a time, stirring until smooth. Transfer icing to a bowl and chill, covered, until slightly thickened and spreadable, about 30 minutes.

　　

Decorate cake:

Step 7

Spread icing over cake with a small metal spatula. Stick points of almonds into cake in straight rows, following ridges, to resemble a porcupine. Chill cake until icing is set, at least 1 hour. Transfer cake to a platter and bring to room temperature before serving.

　　Cooks' note:

　　• You can chill iced cake, loosely covered, up to 3 days.