It was 1984. We had just bought our first house, an old farmhouse built in the late 1800s. The kitchen was outdated and needed renovation. There wasn't a range hood over the stove, and over the years, the ceiling and cabinets had acquired a dingy brownish-grey patina from the buildup of decades of smoke and cooking grease.
Cajun food was all the rage back then, thanks to Paul Prudhomme and his recently released cookbook Chef Paul Prudhomme's Louisiana Kitchen. One of his dishes, blackened redfish, had become a national craze and was so popular that it nearly decimated the entire redfish population in the Gulf of Mexico. Demand for the fish had soared to such unprecedented levels that the National Marine Fisheries Service was forced to ban the commercial harvest of the species in federal waters. We decided to try out Prudhomme's recipe with local Illinois catfish.
We dipped the fillets in melted butter, like Prudhomme instructed, and dredged them in a Cajun spice blend that included paprika, cayenne pepper, garlic powder, onion powder, salt and black pepper. We put our biggest cast-iron skillet on the stovetop and cranked the burner all the way up. When the skillet was ripping hot, we tossed in a little butter and cautiously laid down our catfish fillets. In a matter of seconds, the kitchen filled with smoke so dense that we couldn't see past our hands. The smoke alarm was blaring. Our eyes were watering. Our throats and sinuses were burning. We were coughing uncontrollably. I threw open all the doors and started fanning out the smoke with a cookie sheet.
The smoke eventually dissipated. But during our debacle the kitchen was invaded by thousands of flies that had been attracted to the smell. Our catfish had gone from blackened to inedible and we had to spend the next several days swatting flies. It wasn't until years later, after we remodeled the house and installed a $3,000 range hood, that we attempted to blacken fish ever again.
From a food science perspective, blackening is a phenomenon that lies somewhere between browning and burning. Browning occurs when water is driven off and the proteins or sugars in the food have undergone either Maillard reaction or caramelization, two chemical reactions that result in new flavor compounds that smell and taste appealingly complex. Blackening refers to coating quick-cooking proteins in a Cajun spice blend and flash-cooking them in a ripping-hot cast-iron skillet until the fat and spices smoke and char but don't completely burn. The characteristic deep brown to black color of the crust of blackened fish results from a combination of browned milk solids from the butter and charred spices. The blackening that occurs when food chars isn't just a further degree of Maillardization or caramelization. It's a different set of reactions entirely: pyrolysis and carbonization.
Pyrolysis is essentially burning. The term refers to decomposition brought on by high temperatures. When proteins and sugars are heated to temperatures above 350 degrees, the compounds they formed during Maillardization and caramelization break down even further into smaller molecules that, when taken too far, will taste tarry, smoky and bitter. When taken past browning and brought just to the "edge" of charring, food will develop even deeper, more complex profiles.
A cast-iron skillet is the ideal vessel for getting perfectly blackened fish. The pan can be heated until it is white-hot, which is key to creating the dark brown, crusty, smoky, toasted-spice exterior that is characteristic of this dish.
Paul Prudomme's Blackened Redfish
A controlled blackening pushes the flavor of this Cajun spice-rubbed fish to a higher level.
For the spice mixture:
1 tablespoon paprika
2½ teaspoons kosher salt
1 teaspoon onion powder
1 teaspoon garlic powder
1 teaspoon ground cayenne
½ teaspoon dried thyme
½ teaspoon dried oregano
For the fish:
1½ cups unsalted butter, melted
6 firm-fleshed skinless fish fillets, such as red snapper, mahi-mahi, grouper, haddock, cod, halibut, catfish
Note: To properly blacken fish, the fillets need to be thin enough to cook quickly without burning. They should not be thicker than 1⁄2 inch. A thicker piece of fish should be sliced laterally to make 2 thinner slices.
In a small bowl, combine the paprika, salt, onion powder, garlic powder, cayenne, thyme and oregano. Mix well. Set aside.
Place a large cast-iron skillet over high heat until very hot, about 10 minutes. It will get smoky, so open your windows, disarm your smoke alarm, and turn on your hood vent if you have one.
Meanwhile, pour 2 tablespoons of melted butter into each of 6 small ramekins; set aside and keep warm. Pour the remaining butter into a shallow bowl. Pat the fish fillets dry with paper towels. Dip each fillet in the butter so that both sides are well coated. Sprinkle the spice mixture generously and evenly on both sides of the fish, pushing it into the flesh with your fingers.
When the skillet is fully heated, place the fillets inside without crowding and top each with 1 teaspoon of melted butter. Cook uncovered until the underside looks charred, about 2 minutes. Using two fish spatulas, turn the fillets over and again add 1 teaspoon of butter on top; cook until done, about 2 minutes more. The fish is done when it flakes apart under gentle pressure of your fingers. Transfer to warmed plates and repeat with the remaining fish. Serve immediately, with a ramekin of butter on each plate.