1. Preheat oven to 350 degrees. Grease 20 cm by 20 cm glass baking dish. In large bowl, combine sugar, flour, and salt. With wire whisk, beat in milk, egg yolks, melted margarine or butter, lemon juice, orange juice, and orange peel.
2. In small bowl, with mixer at high speed, beat egg whites until soft peaks form. Fold one-fourth of whites into orange mixture; gently fold in remaining whites. Pour batter into baking dish.
3. Set baking dish in roasting pan; place on oven rack. Carefully pour boiling water into roasting pan to come halfway up sides of baking dish. Bake 40 minutes or until top is golden and set (dessert will separate into pudding and cake layers). Cool in pan on wire rack 10 minutes, then serve right away.