Spread butter on cut sides of buns. Place, cut side down, in pan, and cook until golden brown, 1 to 2 minutes.
Sprinkle salt and pepper all over fish, rubbing to coat. Add to pan, and cook over medium-high heat until fish is browned and flakes easily with a fork, 3 to 4 minutes per side.
Spread 1 to 2 tablespoons Chipotle Mayo on cut sides of buns. On bottom half of buns, layer lettuce, tomato, and fish. Cover with top half of buns. Serve immediately.
Chipotle Mayo
In a small bowl, stir together all ingredients. Refrigerate in an airtight container for at least 30 minutes or up to 1 week.
Recipe by Louisiana Cookin' at https://louisianacookin.com/seared-grouper-sandwiches-chipotle-mayo/