Lemon Sponge Pudding

Preheat oven to 350 degrees F. Lightly oil four 6-ounce custard cups or ramekins or coat them with cooking spray.

Beat sugar, whole egg, butter and lemon zest in a mixing bowl with an electric mixer until the mixture is thick and pale, about 3 minutes. Add flour and beat until smooth. Add milk and lemon juice and beat until well blended.

Beat egg whites in a clean mixing bowl using clean beaters until stiff but not dry. Gently fold the whites into the egg-sugar mixture until completely incorporated.

Spoon the mixture into the prepared cups. Set in a shallow baking dish and add enough hot water to come two-thirds of the way up the sides. Bake until browned and set, about 30 minutes. Serve warm or chilled, dusted with confectioners' sugar.