I had never heard of a king cake until my roommate's parents sent her one from their home in New Orleans this past week. Although I didn't get the full experience (and nobody got the traditional baby in the cake because the bakery packaged the tiny plastic effigy separately), she did bring me home a slice of the green and purple sugar-coated pastry. Even after four days of sitting in her office, the cake maintained its moisture so I happily dug in. It had a briochelike texture and flavor and the inside was spiced like coffee cake, a nice surprise as it wasn't too sweet but was perfect for a breakfast treat.
There are a few different types of king cake, like the galette des rois, which looks more like a pie. The more traditional Mardi Gras version is usually shaped in a ring and topped with colored icing. You can get them stuffed with various things like cream cheese, dried fruit, or the classic cinnamon and sugar version. The three colors on top of the cake represent justice (purple), faith (green), and power (gold).
If you want to make one of these pretty, delicious cakes for your Mardi Gras party, follow the recipe from mardigrasday.com, a company claiming to have sold the first king cake online, or there's a good one by Cajun chef Ryan Boudreaux.
Just watch out for the baby—if you find him in your slice, you have to buy the cake next year.