In shallow dish or bowl, combine thyme, oregano, paprika, chilli powder, salt, hot pepper flakes and pepper.
Heat large cast-iron skillet over high heat until pan begins to turn white, about
5 minutes. Brush both sides of fillets with butter. Dip each into herb mixture; drizzle fillet with some of the butter.
Place fillets in hot skillet; cook, turning once and drizzling with 1 to 2 teaspoons
(5 to 10 mL) more butter, for 6 to 10 minutes or until fish is opaque and flakes easily when tested, reducing heat if herb mixture begins to burn. Serve with lemon.