Blackened Fish - cooking recipe

Ingredients

fish fillets or steaks (1/2 to 3/4-inch thick; we like salmon or swordfish but any firm fish will work)
butter, melted
Paul Prudhomme's blackened redfish seasoning

Preparation

Heat a large cast-iron skillet over very high heat until it is beyond the smoking stage and you see white ash in the skillet bottom.
The skillet must heat at least 10 minutes.
I find using a gas grill works best for this.
Coat both sides of fish generously with seasoning, patting it in by hand.
Place fish in skillet and pour 1 to 2 teaspoons melted butter on top of each fillet.
(Be careful; butter may flare up.)
Cook uncovered until the underside looks charred (2 to 4 minutes).
Turn fish over; top again with melted butter and cook until done (2 minutes).
Serve immediately with extra butter, if desired.