Prepare Tartar Sauce: Combine all ingredients together in a medium bowl, mix well, and taste for seasoning. Place in a covered container and refrigerate, overnight for best flavor, or until ready to use.

Prepare grill: Clean grill grate with a grill brush, then rub down with a cloth that has been lightly oiled with plain vegetable oil (seasoning the grate). Start a medium-hot fire in the grill and place grill grate about 4 inches above the bed of hot coals. Just before grilling, brush top of grate, again, with vegetable oil to help keep fish from sticking.

Prepare Grouper: Grouper filets should be about seven ounces each, thick and fresh. Rinse fillets under cold water and pat dry with paper towels. Season with salt and pepper to taste and brush with clarified butter. Place fillets on oiled, preheated grate, and grill for 4 to 5 minutes on each side (carefully turning only once), or until fish flakes easily when tested with a fork (fish should be white and opaque throughout, with an an internal temperature of 145 degrees).

Assemble Sandwiches: Spread about 2 1/2 tablespoons of Creole Tartar Sauce over cut sides of each bun. Place a couple lettuce leafs on bottom half of each bun. Top lettuce with fish, add slices of tomato if desired, then top with remaining bun halves.