Chocolate Roll
["5 egg yolks", "1 c. confectioners sugar", "1/4 c. flour", "1/2 tsp. salt", "3 Tbsp. cocoa", "1 tsp. vanilla extract", "5 stiff-beaten egg whites"]
["Beat egg yolks until thick and lemon-colored.", "Add sifted dry ingredients and beat until well blended.", "Add vanilla extract and fold in egg whites.", "Spread in greased, waxed paper-lined 10 1/2 x 15-inch jelly roll pan.", "Bake in moderately hot oven (375\u00b0) for 15 to 20 minutes."]
["egg yolks", "confectioners sugar", "flour", "salt", "cocoa", "vanilla extract", "egg whites"]