A pudding cake is a mashup of a souffle and a cake, and it conveniently comes out just as it sounds: cake on top with pudding on the bottom. Pudding cakes have been popular for decades. There is even a recipe in "The Original Boston Cooking-School Cook Book," first published in 1896, for a lemon souffle sponge. It's still delicious enough to enjoy today.

What's the secret science in this rediscovered classic? It seems that when you combine whipped egg whites with the thin cake batter, the dessert cooks up with two layers. It's a bit of magic in a dish! The mixture bakes up into a sponge cake on top with a pudding layer underneath. This light, citrusy dessert is easy to make and welcome after a heavy meal.

When serving, spoon the pudding sauce over the cake. I like the lemon-lime combination, but you can switch out the lime zest and juice for orange if you like.

Two different baking dishes yield two different results. If you use a souffle dish, the cake will have a larger amount of pudding. If you use the rectangular baking dish, the dessert will look like a light souffle cake with a thin pudding layer on the bottom. Whichever you choose, be sure to serve it warm, with a dollop of whipping cream.

Citrus Pudding Cake

Serves 4 to 6

3/4 cup sugar, plus 2 tablespoons

2 tablespoons unsalted butter, softened to room temperature

2 teaspoons lemon zest

1 teaspoon lime zest

3 large eggs, separated

1/4 cup all-purpose flour

2 tablespoons strained fresh lemon juice

2 tablespoons strained fresh lime juice

1 cup half-and-half

1/2 cup whipping cream, whipped, optional

Fresh seasonal berries, optional

1. Preheat oven to 350 F.

2. Beat the 3/4 cup sugar, butter and citrus zests together until creamy and well blended. Add the egg yolks, and beat until blended. Stir in alternately the flour, citrus juice and half-and-half until well blended.

3. In a medium bowl, or electric mixer, beat the egg whites with the remaining 2 tablespoons sugar until stiff. They should hold a peak and be shiny.

4. Fold the egg whites into the egg yolk mixture until just incorporated, and pour into a 6-cup baking dish. Set dish in larger baking pan. Add enough water to reach halfway up the sides of the dish. Bake 45 minutes or until set. Serve hot with whipped cream or berries, if desired. This should be prepared right before serving.

(Diane Rossen Worthington is an authority on new American cooking. She is the author of 18 cookbooks, including "Seriously Simple Parties," and a James Beard Award-winning radio show host. You can contact her at www.seriouslysimple.com.)