Line bottom of 15-1/2 x 10-1/2 x 1-inch jelly-roll pan with parchment paper or line with foil (extending slightly over sides; grease foil).
In small bowl, stir together 1/3 cup cocoa and water until mixture is smooth. Stir in butter and vanilla; cool.
In large bowl, combine egg yolks and 1/2 cup sugar; beat on medium speed of electric mixer until light and fluffy, about 5 minutes.
Add chocolate mixture and almonds, beating until well blended.In another large bowl, beat egg whites until foamy. Gradually add remaining sugar, beating until stiff peaks form. Fold 1/4 egg white mixture into chocolate mixture. Add remaining egg whites, folding well.
Pour batter into prepared pan. Bake 18 to 20 minutes or until cake springs back when touched lightly in center.
Dust cake with 1 tablespoon cocoa; cover with clean dry towel. Cool in pan on wire rack. Cut cake into 4 equal pieces. Remove paper or foil before placing on serving plate.
2Prepare COCOA WHIPPED CREAM; reserve 1-1/4 to 1-1/2 cups to frost sides and ends of cake.
Place one layer on plate; spread with COCOA WHIPPED CREAM. Repeat layering, ending with whipped cream. Spread reserved whipped cream on all sides of assembled cake.
Garnish as desired.
Refrigerate until serving time. Cover; refrigerate leftover dessert.
COCOA WHIPPED CREAM
In large cold bowl, combine 1-1/2 cups cold whipping cream, 1/3 cup sugar, 3 tablespoons HERSHEY's Cocoa and 3/4 tablespoon vanilla extract; beat with cold beaters until stiff. About 3 cups whipped cream.
* To toast almonds: Heat oven to 350 F. Spread 1/3 cup blanched slivered almonds in thin layer in shallow baking pan. Bake 8 to 10 minutes, stirring occasionally, until light golden brown. Cool. To grind, process in food processor.