On a large piece of wax paper, mix together all seasoning ingredients excpet salt. In a small saucepan over medium heat, melt butter with oil. Brush both sides of snapper fillets with some butter- oil mixture, coat both sides of fish lightly with seasonings. Reserve remaining butter-oil mixture. Heat a large cast - iron skillet over high heat until a drop of water sizzles on it. Drizzle half or remaining butter-oil mixture on one side of fish fillets. Place fillets butter side down in pan. Cook on high heat until deeply browned, about 5 minutues. Drizzle on remaining oil mixture and turn fish over. Add more oil if needed. cook until fish is browned and flakes when tested with a fork, about 5 minutes longer.
Season to taste with salt.