This recipe is designed for large fish, originally the redfish of the Gulf States. Any fish with heavy scales will work, however. In this case I am using a large yelloweye rockfish, but you could also use a California sheepshead, pargo, largemouth or smallmouth bass, grouper, snapper, a big black seabass... you get the point. The one vital thing you need is a piece of fish with the skin and scales left on. If you don't have that, you cannot make this recipe. The scales protect the fish from the high, direct heat of the grill. All you do is slap that puppy on the grill and watch the magic happen. It's super, super easy.
2to 3 pounds large fish filletswith the skin and scales still on
2to 3 tablespoons Cajun seasoning
1/2to 1 teaspoon cayenne pepper
Mix the salt and water until the salt dissolves, then add the ice. Brine the fish for 1 hour. Remove, pat dry with paper towels and put on a rack in a cool, breezy place for 30 minutes. While you are doing this, get your grill nice and hot.
When you grill is ready, coat the fish with the vegetable oil, then sprinkle the meat side of the fish with the Cajun seasoning. Lay the fish on the grill with the fat side of the fillet over the hottest part of the fire, and the tail sections out toward the edge where the fire is a bit cooler. Let the fish grill undisturbed until the meat is fully cooked; it will just begin to flake when that happens. This can be done in an uncovered grill if it's a) not too windy, and b) the fillet is less than 2 inches thick. If you are worried about timing, cover the grill, or tent the fish with some heavy-duty foil.
When the fish is done, gently remove it with a large spatula, or two spatulas if you need to. Move it to a platter and dot the top of it with the butter. Serve when the butter melts alongside rice, potato salad, maque choux, etc.
Serve the fish with grilled vegetables, rice, potato salad or something simple. This is, to me, beer food. Wine? Maybe an off-dry Riesling, an oaky Chardonnay, a decent rose. But nothing too fancy.