Mardi Gras is supposed to represent a farewell to the fat, or flesh, as traditionally symbolized by the fatted bull or ox (boeuf gras). But nowadays king cake, a festive oval pastry made from cinnamon-infused brioche dough, is the most widely recognized symbol of pre-Lenten feasting and the most popular way to share the Mardi Gras spirit. It customarily appears on Epiphany, also known as Twelfth Night, but is most in demand in the days leading up to Fat Tuesday.

Along with beads and parade floats, king cakes have come to symbolize the notion of Mardi Gras as a time of boisterous frivolity. Indeed, no Mardi Gras party is complete without a king cake festooned in the Mardi Gras colors of purple, green and gold/yellow.

A tasty excuse to cut loose, king cake is also, thanks to express shipping, a fabulous gastronomic greeting: an expression of good will for corporate customers as well as friends and family members unable to experience the festivities in person.

Included with each cake is a small plastic “baby” typically hidden in the dough or underneath the cake. In New Orleans, popular custom holds that the finder of the baby must purchase the next cake and throw a party.

King cake came to be associated with Mardi Gras because its traditional appearance on Twelfth Night signals the start of the season of merriment and make-believe (Carnival) that runs through Fat Tuesday. (Because the day before Ash Wednesday, which marks the beginning of Lent, was one of feasting, it came to be known as Fat Tuesday or, as the French would say, Mardi Gras.)

In the story of the Epiphany, as related in the gospel of Matthew, “three wise men from the east” visited the baby Jesus in Bethlehem on the twelfth day following his birth. Epiphany became the day appointed by the Church to celebrate the revelation of Christ’s divinity to mankind.

In the 4th century, the western world’s most influential preacher, St. Augustine, romanticized and embellished the story of the Epiphany. The gift-bearing wise men became “kings,” and Feast of the Epiphany, the twelfth day of Christmas, evolved into a major holiday imbued with royal associations.

While the Twelfth Night customs that spread throughout Europe were subject to numerous variations, one element transcended virtually every culture that observed the holiday: the choice of a mock king for the occasion. The ritual of hiding a tiny treasure in a celebratory cake became a symbolic reenactment of Epiphany. In France, the bean—la feve—eventually was replaced by a bean-sized baby Jesus; its discovery commemorated the discovery of Jesus’ divinity by the Magi. Legend has it that the cakes were made in the shape of a ring and colorfully decorated to resemble a bejeweled crown.

It became a tradition to serve the cake with paper or cardboard crown on top. Whoever found the hidden trinket, would get to wear the crown and choose a royal consort.

In colonial New Orleans, Creoles, as residents of French and Spanish decent took to calling themselves, adopted the French Twelfth Night cake custom and melded it with their party-loving ways—in particular, the Spanish custom of throwing grand balls where a king and queen were chosen.

By the late 18th century, a season of balls, called les bals des Rois (the balls of kings), was well established. On Twelfth Night, the celebrants would wait until the stroke of midnight to cut the cake—a French-style pastry, gateau des Rois, filled with frangipane (made from almond paste, eggs, butter and sugar). Inside was a bean, almond, pecan or perhaps even a jeweled ring. 

Each week a new king and queen were crowned (the finder of the hidden trinket would get to chose his or her consort). The reigning queen would host the next soiree at her home; the king, however, was expected to foot the bill.

The role of king cake in divining Carnival royalty is most closely associated with the Twelfth Night Revelers (TNR). One of New Orleans Carnival’s most socially elite organizations, TNR held its first pageant on January 6, 1870—a procession of floats, or tableaux roulants (rolling tableaux), followed by a grand Twelfth Night ball.

TNR once used a real cake with hidden trinkets. Nowadays, it deploys a mock cake chock-a-block with small boxes. Each box contains either a small piece of real cake or a bean on a chain. As orchestrated by krewemen, who are assisted by pre-teen boys got up as "junior cooks," only the debutantes designated to serve as maids in the court receive boxes with beans. All but one of the debs is handed a box with a silver bean.  Whoever receives the box with the gold bean, is crowned queen.  

This being the realm of make-believe, the fact that her royal fate is actually predetermined is beside the point: The ritual is designed to perpetuate the illusion that the Goddess of Chance has exerted her will through the "luck of the bean."

While the practice of using king cake to choose royalty was never widely imitated by other Carnival krewes, the toothsome treat nevertheless became more than just a symbol of the festivities: At weekend king cake parties, generations of New Orleans children became familiarized with the concept of mock royalty—a concept fundamental to the rituals of Carnival—and teenagers learned the social niceties of drinking, dancing and mingling with members of the opposite sex.

Alas, times have changed. Nowadays, teenagers are more likely to have king cake in school than at king cake parties.  As for adults, offices have become a prime venue for seasonal rituals involving king cake.

The cakes themselves have changed, as well. The almond-paste-filled pastry puff that’s traditionally associated with northern France—the gateau des Rois enjoyed by the old Creole gentry in New Orleans—can still be found at some specialty bakeries. But by far the most popular style of king cake these days has more in common with the Bordeaux Twelfth Night cake of southern France—the couronne, French for crown, which is made from brioche dough. (Key differences: The New Orleans version is rolled with cinnamon, covered with purple, green and gold sugar or sprinkles and typically comes iced rather than glazed.)

Meanwhile, thanks to the advent of express-shipping services, New Orleans king cake culture has spread throughout the United States and beyond. As a result, “I got the baby!”—the cry announcing that a party-goer has received the slice of cake with the plastic baby—is literally, during Mardi Gras time, a cry heard round the world.