In a mixing bowl combine the salt, sugar, spices, and pepper with a whisk to break up any sugar clumps.
Place 1/3 of the cure in a layer in the bottom of a non-reactive baking dish (glass works best).
Place 2 of the fish, open and flat, skin side down, on top of the cure and press down lightly.
Press another 1/3 of the cure into the flesh of the fillets.
Place the other 2 fillets of fish on top of the cure that is on the bottom fillets, flesh side down.
Pack the remaining cure on top of the fish and around the sides of the fish.
Cover the dish with plastic wrap and place in the refrigerator for 8 to 12 hours, or overnight.
Remove the fish fillets from the dish and rinse under cool running water.
Pat the fillets dry with paper towels.
Place the open and flat fillets, skin side down, on a rack inside a sheet tray.
Place this in the refrigerator for 2 to 3 hours to allow the fish to air dry.
Take the tray out of the refrigerator well before you prepare your smoker, approximately 45 minutes, to allow the fish to come to room temperature.
Preheat your smoker to between 120˚F and 170˚F (lower if you have time to kill).
Add the wood chips to the side tray or the bottom of the smoker, depending on whether you are using electric or charcoal.
Add water to the smoker bowl with the lemon slices.
Open the top vent to allow for some smoke to release.
While the smoker is warming up, mix together the olive oil and seasonings.
Brush this on the flesh side only of the fish.
Place the butterflied fish fillets, skin side down, directly on a rack inside the preheated smoker.
Smoke for 1 hour, and then check the internal temperature.
You are looking for approximately 140˚F to 145˚F. Continue smoking until that proper temperature is reached.
Replenish the water and wood chips as needed, approximately every 60 minutes.
You will know it is time if you don’t see any smoke from the vent.
The total smoking process may take 2 to 3+ hours low and slow depending on the temperature of your smoker.
Naturally, this is the best part of the steps.
You can serve your mullet just as it is with some lemon wedges and some toasted baguette slices.
Smoked fish can be served either warm or at room temperature.