Any size piece of Rockfish fillet will do. Remove all dark meat. Take a fillet and coat both side with melted butter. Sprinkle both sides heavily with Paul Purdonne Seafood Blackening rub. It cost $3.50 at all grocery stores. Heat cast iron skillet on gas stove or better yet on side burner on gas grill outside for about 10 minutes. Cook fillets @ 4-5 minutes a side. Its gonna get smokey if you do this in the house. Remove fish from pan and bake in oven at 350 degress for @ 15 minutes to make sure inside gets done all the way. Thicker fillets require no more than 15 minutes. Serve with rice and cold beer and watch your tongue "slap your brain"