Moist Lemon Angel Cake Roll

Directions

1. Line a 15x10x1-in. baking pan with waxed paper; lightly coat paper with cooking spray.
2. Preheat oven to 350°. Add vanilla and cream of tartar to egg whites; beat on medium speed until soft peaks form. Gradually beat in sugar, 2 Tbsp. at a time, on high until stiff glossy peaks form and sugar is dissolved. Fold in flour, about 1/4 cup at a time.
3. Gently spread batter into prepared pan. Bake until cake springs back when lightly touched, 15-20 minutes. Cool 5 minutes.
4. Turn cake onto a kitchen towel dusted with 1 tablespoon confectioners’ sugar. Gently peel off waxed paper. Roll up cake in the towel jelly-roll style, starting with a short side. Cool completely on a wire rack.
5. In a large saucepan, combine sugar and cornstarch; stir in water until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat; cook and stir 2 minutes. Remove from heat. Stir a small amount of hot mixture into egg; return all to the pan, stirring constantly. Bring to a gentle boil; cook and stir 2 minutes.
6. Remove from heat. Gently stir in lemon juice, zest and, if desired, food coloring. Cool to room temperature without stirring.
7. Unroll cake; spread filling to within 1/2 in. of edges. Roll up again. Place seam side down on a serving plate; sprinkle with additional confectioners' sugar.