Atomic Cake

If you’re ever in a bakeshop on Chicago’s South Side, you’ll probably see a towering confection that stacks three cakes into one glorious treat. Welcome to the world of Atomic Cake, where layers of banana melt into fluffy custard, tangy reverberations of strawberry are cut short by deep, rich chocolate, and everything is shrouded in a blanket of whipped cream.

To build this gargantuan delight, bakers are tasked with whipping up three different cake bases—banana, yellow, and chocolate—then layering fillings and fruit throughout. After packing in the likes of Bavarian cream custard, fresh bananas, and glazed strawberries, the pastry chef tops each cake with a layer of fudge and a slathering of whipped cream (or, occasionally, buttercream).

South Side bakeries have been selling the cake since the 1950s. Generations of South-siders think of milestones and rites of passage, particularly birthdays, as cause for the treat. You won’t see kids enjoying a slice after school, because bakeries don’t sell the behemoth creation a la carte. If someone wants an Atomic Cake, they’re buying the whole thing.

No one’s sure who invented Atomic Cake, why it rarely leaves the South Side, or how it got its name (though the first nuclear reactor was built in Chicago’s Hyde Park in 1942). Michael Weber, president of the South Side’s oldest bakery, just knows the neighborhood treat is distinctly theirs: “I’ve been to a lot of bakeries around the country, and they don’t do Atomic Cakes,” he said. “They don’t even know about it.”