Baked Catfish Po'Boys with Cajun Remoulade

3/4 C. buttermilk
3 Tbsp. course grain Dijon mustard, divided
3 tsp. hot sauce, divided
3 tsp. Cajun seasoning mix, divided
4 catfish fillets (about 1 1/4 lbs)
1/2 C. unseasoned cornmeal fish fry mix
1/2 tsp. salt
1/2 tsp. black pepper
1/4 C. reduced fat mayonnaise
1 tsp. Worcestershire sauce
olive oil cooking spray
four 5in. sections of crusty French bread or hoagie rolls, halved horizonatally
2 C. shredded romaine lettuce
1 lg. tomato, thinly sliced

Whisk together the buttermilk, 2 Tbsp. of the mustard, 2 tsp. of the hot sauce, and 1 tsp. of the Cajun seasoning. Add the catfish fillets. Cover with plastic wrap, and refrigerate for at least 20 min. or up to 2 hrs.
Blend together the fish fry mix, 1 tsp. Cajun seasoning, salt, and pepper. Set aside.
To make the remoulade, whisk the mayonnaise, Worcestershire, the remaining Tbsp. of mustard, the remaining tsp. of hot sauce, and the remaining tsp. of Cajun seasoning.
When ready to cook the fish, heat the broiler. Use the cooking spray to lightly coat a wire rack large enough to hold the fish in a single layer. Place the rack on a baking sheet.
Remove the fish from the refrigerator and turn each fillet in the buttermilk mixture to recoat. Transfer to cornmeal mixture, turning fillets to coat completely. Lightly mist fillets on both sides with cooking spray and place on prepared rack (they should not touch).
Broil 4 in. from heat source for 3 min., then carefully flip the fillets and broil another 3 min., or until the fish opaque and flakes easily at center.
Assemble the sandwiches by spreading the cut side of each piece of bread with remoulade. On the bottom half of each bread section, layer with catfish fillet, shredded lettuce, sliced tomato, and top piece of bread. Serve immediately.