Pat the catfish dry and cut it into 1½- to 2-inch nuggets. Add the catfish pieces to a large bowl and pour in buttermilk and hot sauce. Toss until every piece is coated. Cover with plastic wrap and refrigerate for 30 minutes. 2 lbs Catfish Fillets1 cup Buttermilk1 tbsp Hot Sauce
While the fish is marinating in the buttermilk, make the Creole tartar sauce. In a small bowl, stir together the mayonnaise, relish, mustard, Cajun seasoning, sugar, garlic powder, hot sauce, and lemon juice. Refrigerate while you prepare the fish so the flavors have time to blend. 1/2 cup Mayo2 tbsp Relish1 tbsp Yellow Mustard1 1/2 tsp Cajun Seasoning 1 tsp Sugar 1/2 tsp Garlic Powder1 tbsp Hot Sauce2 tbsp Lemon Juice
Drain the buttermilk mixture from the catfish, allowing the excess to drip off. Do not rinse the fish. Into a clean bowl, add the drained buttermilk and add the yellow mustard, Old Bay, and Cajun seasoning, then gently toss until the nuggets are evenly coated. 1 tbsp Yellow Mustard1 tsp Old Bay 1 tsp Cajun Seasoning (Note: Drain the Buttermilk Thoroughly. You want the fish moist enough to hold the breading, but not dripping wet. Too much marinade can create gummy patches in the coating.)
In a large shallow bowl or resealable bag, combine the flour, cornmeal, Old Bay, Cajun seasoning, onion powder, garlic powder, and black pepper. Mix well so the seasonings are evenly distributed. 1 cup All Purpose Flour 1 cup Fine Ground Cornmeal1 tbsp Old Bay2 tsp Cajun Seasoning 1 1/2 tsp Onion Powder 1 1/2 tsp Garlic Powder1/2 tsp Black Pepper
Working in batches, add the catfish nuggets to the flour mixture and toss or shake until thoroughly coated. Press the coating lightly onto the fish, then shake off any loose excess flour.
Pour about 3 inches of oil into a deep, heavy-bottomed pot. Heat the oil to 350°F. A thermometer is best here, the oil needs to be hot enough to crisp the coating without burning it.
Carefully lower the coated catfish into the hot oil without overcrowding the pot. Fry for 4 to 6 minutes, turning as needed, until deeply golden, crisp, and cooked through. The fish should be opaque and flake easily, with an internal temperature of 145°F.
Remove the catfish nuggets from the hot oil with a spider or slotted spoon and place onto a wire rack set over a baking sheet. Immediately sprinkle with a little Cajun Seasoning, if desired. Let the oil return to 350°F before frying the next batch. Serve hot with the Creole tartar sauce and fresh lemon wedges.
Notes
Do Not Marinate the fish too long. Catfish nuggets are small and only need about 30 minutes in the buttermilk. A long soak is unnecessary and can make the fish mushy.
Press the Coating Onto the Fish. Do not simply drop the nuggets into the flour and immediately pull them out. Toss and gently press the mixture onto each piece so the cornmeal coating sticks.
Let the Breaded Catfish Rest. Resting the coated nuggets for approximately 10 minutes allows the flour to absorb some moisture from the fish. The coating should look slightly damp in a few spots before it goes into the oil.
Do Not Overcrowd the Pot. Adding too many cold pieces at once lowers the oil temperature. The nuggets need space for the hot oil to circulate around them and crisp the entire surface.
Drain on a Wire Rack. Paper towels can trap steam underneath the nuggets and soften the crust. A wire rack allows air to circulate so the coating stays crunchy.