Heat oven to 375°. Grease bottom only of 15X10-inch jelly-roll pan. Line with parchment paper and grease again. Lightly spoon flour into measuring cup, level off. In medium bowl, combine flour, first 1/2 cup sugar, baking powder and salt. In a large bowl, beat egg yolks at high speed until a light lemon color. Add second 1/2 cup sugar and continue beating until thickened. Add cold water and 2 teaspoons lemon zest, mix well. Gently fold flour mixture into egg mixture, blend well. Spread batter in prepared pan. Bake 15 to 18 minutes until light golden. Remove from oven and immediately turn out of pan onto a towel sprinkled with powdered sugar. Quickly remove paper. Starting at short side, roll up in towel; cool completely.
In a small heavy saucepan, combine sugar, salt, lemon juice and egg yolks. Cook over low heat until thickened; stirring constantly. Remove from heat and stir in lemon peel; cool. Whip cream to soft peaks and fold into cooled filling. Unroll cake, spread with filling and roll again without towel. Refrigerate 1 to 2 hours. (Inspired from recipe in "Pillsbury Bake-Off Classics III.)
*One lemon yields 1 tablespoon (3 teaspoons) lemon zest and 1/4 cup (4 tablespoons) juice.