1. Heat oven to 350°F. Butter 9-inch springform pan.
2. Spread almonds on ungreased cookie sheet. Bake 12 minutes or until golden brown and fragrant; cool completely. Place almonds in food processor with 1/2 cup sugar; process until finely ground.
3. Break chocolate into pieces; place in medium microwave-safe bowl. Microwave at MEDIUM (50%) 1 minute; stir. If necessary, microwave at MEDIUM an additional 15 seconds at a time, stirring after each heating, until chocolate is melted and smooth when stirred. Set aside.
4. Beat egg yolks with 1/2 cup sugar in large mixer bowl with electric mixer at hedium-high speed about 8 minutes or until very thick and pale. (The mixture will form a ribbon when the beaters are lifted.) Fold in chocolate mixture; set aside.
5. With clean beaters, beat egg whites and salt in large deep bowl just until soft peaks are formed. Gradually beat in remaining 1/2 cup sugar just until stiff peaks form.
6. Gradually fold almond mixture into chocolate mixture. (Mixture will be very thick.) Gradually fold in egg white mixture, just until blended. Gently spoon mixture into prepared pan. Level top with rubber scraper.
7. Bake 55 to 60 minutes or until wooden pick inserted in cake center comes out clean, but moist and cake is pulling from pan sides. (Do not overbake.) Cool completely in pan on wire rack. As the cake cools the center will sink.
8. To serve, run table knife around edge of cake; remove pan sides. Place on serving plate; generously dust cake top with cocoa. Cut into wedges; garnish as desired. 8 to 10 servings.