Begin by patting the catfish fillets dry with paper towels to remove excess moisture, which will help achieve a crispy blackened crust. Generously season both sides of the fillets with the spice mix, ensuring each piece is well-coated. Allow the seasoned fillets to rest for about 10 minutes on a plate, letting the flavors permeate the fish before cooking.

Heat a cast-iron skillet over medium-high heat until it’s hot but not smoking. Add unsalted butter and let it melt, swirling the pan to coat. Carefully place the catfish fillets in the skillet and cook for 3–4 minutes, or until the undersides are dark and charred. Flip the fillets and cook for an additional 3–4 minutes, until they are golden brown and cooked through. Remove the fish from the skillet and set aside.

In the same skillet, add another unsalted butter, allowing it to melt and pick up those delicious residual bits from the fish. Toss in the chopped onion and sauté for 2–3 minutes until the onion becomes translucent and fragrant. Next, add the minced garlic and stir for about 1 minute.

Pour in the shrimp stock and heavy cream, stirring to combine with the onion and garlic mixture. Add the freshly squeezed lemon juice to brighten the sauce, along with the optional crawfish, shrimp, and oysters if using. Allow the mixture to simmer for 4–5 minutes until it thickens.

Return the cooked catfish to the skillet, nestling the fillets into the creamy sauce. Spoon the velvety sauce generously over the fish and let it cook for an additional minute, allowing the flavors to meld beautifully.

Carefully plate the catfish fillets, generously draping the creamy sauce over the top. Finish off with a sprinkle of fresh parsley for a vibrant touch. Serve hot.