Lemon Lime Angel Cake Roll

Adapted from Good Housekeeping Magazine

12 servings

In a 2-quart saucepan, with wire whisk, combine sugar, cornstarch, lemon juice, limeade, egg yolk, and water. Mix until well blended. Heat lemon mixture to boiling over medium heat, whisking constantly. Boil one minute, whisking. Remove saucepan from heat. Stir in margarine. Pour lemon mixture into mixing bowl. Cover with plastic wrap. Refrigerate until cool, one and half hours. Meanwhile, preheat oven to 350. Line a jelly-roll pan with 18" long sheet of wax paper. Do not grease wax paper. Prepare cake mix according to package directions. Spread batter into prepared pan. Bake for 20 minutes or until golden brown. Sprinkle top with evenly with powdered sugar. Place clean dish towel and wire rack over top of cake and invert cake in pan. Cool completely. When cake is cool, run spatula around sides of cake to loosen from pan. Remove pan. Peel off wax paper and discard. With spatula, spread cooled lemon-lime filling to within two inches of edges. Starting from long side, roll cake without towel jelly-roll fashion. Place rolled cake, seam side down, on long platter. Refrigerate if not serving right away. Sprinkle with powdered sugar before serving.