In a mixing bowl, whisk the milk, mustard and hot pepper sauce together. Season the mixture with salt and cayenne. Lay the fish in the milk mixture, cover, refrigerate and marinate for 1 hour. In a pie pan, combine the flour, cornmeal and 2 teaspoons of Essence. Remove the fish from the refrigerator and drain. Dredge each fillet in the cornmeal mixture, coating each side completely. In a large cast-iron skillet, heat the vegetable oil. When the oil is hot, gently lay each fillet in the hot oil. Pan-fry the fillets for 2 to 3 minutes on each side, or until the fish is golden brown and the meat is flaky. Remove the fillets from the oil and drain on a paper-lined plate. Season the fish with the remaining Essence. Serve the catfish with the Andouille Smothered Beans.