Place milk in a large bowl; add catfish fillets, turning to coat; let soak 10 minutes. Place a large heavy skillet over high heat. Pour cooking oil to ½ inch deep. 

Remove fillets to a platter and season to taste. Place fish fry or corn meal in a large shallow bowl. Dredge seasoned catfish, turning to coat both sides. When cooking oil shimmers, carefully add catfish, plump side down, and fry until golden brown, 5-7 minutes; turn and brown second side, 3-4 minutes. Remove to paper towels and drain. Allow diners to assemble po’ boys as desired.

Makes 4 po’ boys.