Heat 1/2 inch of oil in a large heavy skillet over medium heat. While oil is heating, rinse catfish fillets and pat dry with paper towels. Place flour in a shallow dish or on a large piece of waxed paper. Place egg or egg whites in another shallow dish. Ditto sesame seeds. Dredge fillets lightly in flour (adding more flour if needed). Dip fillets in egg, then coat with sesame seeds.

Carefully place catfish, one fillet at a time, in the hot oil and cook for 2-3 minutes per side, or until fish flakes easily when tested with a fork. Drain on paper towels. Serve fillets with sauced spooned over them or in a bowl on the side.