Cake Top Lemon Pudding

2 tablespoons margarine
1 cup granulated sugar
4 eggs, separated
3 tablespoons flour
1/2 cup lemon juice
2 teaspoons grated lemon rind
1/4 teaspoon salt
1 cup milk

Cream margarine and sugar. Add egg yolks, flour, lemon juice, lemon rind and salt. Blend well. Stir in milk. Beat egg whites well. Fold into lemon mixture. Pour into 8 custard cups. Place custard cups in pan of hot water in oven. Bake at 325 degrees F for about 40 minutes. Turn up temperature in oven to brown top of pudding.