4fresh grouper fillets(1 to 1-1/2 inches thick) (skinless)
Preheat the oven to 300 degrees F.
Melt butter in a small skillet over medium heat. Add garlic and thyme and cook for about 30 seconds. Stir in panko and pepper and cook until the panko is golden brown, which should take about 6 minutes. Remove from the heat and set aside.
Combine mayonnaise and lemon zest in a small bowl.
Use a paper towel to pat dry the fish fillets and season to taste with salt and pepper.
Set a wire baking rack inside a rimmed baking sheet and spray with non-stick cooking spray.
Use a pastry brush and coat the tops and sides of the fish fillets evenly with a thin layer of the mayonnaise mixture.
Dredge the fillets in the panko breadcrumb mixture and make sure the top and sides are evenly coated. Do not coat the bottom.
Place the fillet, panko side up, on the baking rack and repeat with the remaining fillets.
Bake the fillets for about 30-35 minutes, or until a meat thermometer inserted in the thickest part of the fillet registers 140 degrees and the fish flakes easily when a fork is inserted.
Any firm white fish like red snapper, halibut, flounder, haddock, cod, or mahi-mahi, would also work well in this easy baked fish recipe.