Lemon Sponge Pudding

4 tablespoons unsalted butter
1/4 cup granulated sugar
3 eggs, separated
1/3 cup lemon juice
1/3 cup all-purpose flour
1 tablespoon grated lemon rind
1/4 teaspoon salt
1 1/2 cups milk
Pinch of cream of tartar
Confectioners' sugar
Lemon rind

Heat oven to 350 degrees F.

Cream butter and sugar in a large bowl. Add egg yolks, one at a time, beating well after each addition. Beat in the lemon juice, flour, lemon rind and salt. Add the milk in a steady stream, beating and combining the mixture well.

Beat the egg whites with the cream of tartar in a medium-size bowl until stiff peaks form. Stir one-fourth of the egg whites into the lemon mixture. Gently, but thoroughly, fold in the remaining whites. Pour the mixture into a 1 1/2-quart souffle dish. Set the dish in a deep pan and pour boiling water into the pan to come halfway up the sides of the dish. Bake for about 50 minutes or until puffed and golden brown on the top. Sift the confectioners' sugar over the top. Serve warm or chilled; garnish with lemon rind.