The idea has been around long enough that it has other names elsewhere. That was in a black iron skillet heated as hot as the flame could get it. So Gerhard Brill, the chef de cuisine at Commander's, went down to the kitchen and tried it out. To replace the natural fat that a steak has but a fish doesn't, he dipped the fish in some butter after crusting it with Creole seasoning. When the fish went into the pan, it flamed up.
Chefs love to see flames, so that was satisfying.
So was the taste. Everybody liked it, and it went right onto the menu. A few years later, when the Brennan's opened Mr. B's, they installed the city's first modern wood-burning grill to accomplish the same feat in a more sophisticated way. And when Chef Paul left all this behind to open his new restaurant, he pulled the iron skillet out again and used it to make cooking history. I think the most ridiculous thing I saw was blackened baby white veal.