1. Heat oven to 350°F. Lightly grease 13x9x2-inch baking pan.
2. Beat egg yolks with 2/3 cup sugar in medium bowl until thick and light in color. Combine potato starch and cocoa; gradually add to egg mixture, beating until well blended. Stir in bananas.
3. Beat egg whites in large bowl until foamy. Gradually add remaining 1/4 cup sugar, beating until stiff peaks form. Stir about 1/2 cup beaten whites into cocoa mixture. Gently fold cocoa mixture into remaining egg white mixture, blending well. Spoon batter into prepared pan. Sprinkle almonds over top.
4. Bake 25 to 30 minutes or until top springs back when touched lightly in center. Cool completely in pan on wire rack. (Cake will settle and pull away from edges of pan slightly during cooling.) Cut into squares. About 15 servings.