Some things are magic and should be accepted as such without regard to logic or science. I propose we add cake mixes to that category.

Designed to be idiot-proof, your standard cake-out-of-a-box is made by adding eggs, vegetable oil and water to a pile of powder. Overmix, undermix, forget to grease the pan—you still get an edible cake.

But here's the thing: You don't even need the oil and eggs. Just get the batter wet—plain water will do—and you'll end up with a perfectly nice cake.

Learn something new every day.

My experiments started when my husband came back from visiting family in California with the story of a cake baked by his sister-in-law, Dolores Perez, using a can of Diet Coke and a chocolate cake mix. Period.

Poke around the Internet and you'll find thousands of references to soda cakes: Sprite and white cake, Cherry Coke and spice cake ... on and on.

But why? Eliminate the 1/3 cup oil and three eggs normally added to a box mix and you cut about 88 grams of fat and 600 milligrams of cholesterol. Plus it's cheaper, and you can throw a cake together even if you're out of eggs.

The formula: Add 12 ounces liquid to the mix, then follow the baking instructions on the box. That's a can of soda or 1-1/2 cups of any other liquid.

I made four cakes using Duncan Hines chocolate cake mixes. I tried Diet Coke, regular Coke, club soda and tap water, fully expecting the water cake to be a disaster. But all the cakes baked up the same, which would indicate that carbonation isn't the key. All four rose nicely, tasted chocolaty and were quite moist. The cola cakes had a slight husky cola flavor.

But why? A cake mix includes all the flavoring and sugar you need for taste, as well as powerful leaveners, emulsifiers and preservatives that make the cake rise, give it form and keep it from going stale. Apparently eggs and oil aren't crucial.

Wayne Iwaoka, a University of Hawaii researcher who helps me with questions about food chemistry, says it is the gluten in the flour that supports the structure of the cake. The oil you add tenderizes the cake; the eggs support the gluten structure and also tenderize.

Iwaoka also said a cake baked without oil and eggs might dry out—the water would evaporate. This did happen with my cakes after a couple of days. The cakes were also so soft they were crumbly when cut.

A fifth control cake—which I made with eggs and oil—was much sturdier. If I were to do it over again, I'd add just one egg to the mix, for structure. I see no need for the added fat from the oil, though.

Actually, if I were to do it over again, I'd experiment with other liquids. Coffee, for instance, or whiskey (whoo-hoo!) or even apple juice.

Cola Cake

1 box chocolate cake mix (any type, any brand)
1 12-ounce can diet cola
» Frosting:
1 stick (1/2 cup) butter
1/4 cup unsweetened cocoa powder
1/3 cup cola (regular or diet)
3 to 4 cups powdered sugar

Bake cake according to package directions, using cola in place of eggs and oil, in desired pan size. Cool.

To make frosting: Melt butter over medium heat. Stir in cocoa and cola. When smooth, remove from heat; stir in sugar gradually to reach a texture and sweetness you like. Frost cake, or if cake is too soft to frost, squeeze a dab of frosting onto each piece, using a pastry bag or plastic bag with a hole cut in one corner.

Nutritional information unavailable.

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