HEAT oven to 350°F. Line bottom of 15 x 10 x 1-inch baking pan with foil, shaping so that foil around edges of pan stands upright, at least 2 inches high. (Foil will help prevent batter from running over during baking.) Coat foil lightly with no-stick cooking spray.

PREPARE cake batter according to package directions using water. Spread batter evenly in prepared pan. Bake at 17 to 22 minutes or until golden brown and surface appears dry. Cool in pan on wire rack.

COMBINE sweetened condensed milk, lemon juice and lemon peel in medium bowl; blend well. Fold in strawberries until coated.

REMOVE foil from cake. Cut cake in half crosswise to make two equal size pieces. Place one layer on serving plate. Spread with filling. Cover with top layer. Beat whipping cream and powdered sugar in large bowl with electric mixer on medium speed until stiff. Frost top and sides of cake with whipped cream. Garnish with additional strawberries as desired. Chill until ready to serve.