Combine sugar, flour, milk, lemon rind, juice, salt, and egg yolks in a large mixing bowl; beat well. Set aside.
Beat egg whites (at room temperature) until stiff peaks form. Gently fold beaten egg whites into reserved lemon mixture. Pour batter into an 8 - inch square baking dish. Place baking dish in a pan of boiling water to come halfway up sides of dish. Bake, uncovered, at 325° for 40 minutes or until pudding is lightly browned; cool. Spoon pudding into individual serving bowls.
Oxmoor House Homestyle Recipes