Pat the grouper fillets dry with paper towels. If fillets are thick (over 1 inch), butterfly or gently pound to an even thickness about 1/2 inch so they cook evenly. Season both sides with 1/2 tsp salt and 1/4 tsp black pepper.

Set Up Breading Station

Place the 3 tbs flour on a shallow plate. In a shallow bowl, whisk together the 2 large eggs and 2 tbs whole milk until uniform. On a third shallow plate or rimmed baking sheet, combine 1.5 cups panko, 3/4 cup grated Parmesan, 2 tbs chopped parsley, 1 tbs chopped basil, 1 tbs lemon zest, 1 tsp garlic powder, and the remaining 1/2 tsp salt and 1/4 tsp black pepper; toss to distribute evenly.

Coat Fillets

Working one fillet at a time: lightly dredge a fillet in the flour, shaking off excess. Dip into the egg mixture, letting excess drip back into the bowl. Press both sides of the fillet into the panko-Parmesan mixture, pressing gently so the crumbs adhere and form an even crust. Place coated fillets on a wire rack set over a sheet tray while you finish the rest. If time allows, refrigerate the coated fillets for 10 minutes to help the crust set.

For Frying & Serving

Heat Pan

Add 4 tbs olive oil and 2 tbs unsalted butter to a large nonstick or stainless-steel skillet and heat over medium-high until the butter foams and the oil shimmers (about 2–3 minutes). The fat should be hot enough that a few panko crumbs sizzle on contact.

Pan-Fry Fillets

Carefully add fillets to the pan, crust-side down. Do not overcrowd; cook in batches if needed. Cook without moving for 3–4 minutes, until the crust is golden brown and releases easily. Gently flip and cook the second side 2–3 minutes more, or until the internal temperature reaches 135–140°F (57–60°C) and the fish flakes easily. For thicker fillets, cover the pan for the last minute and reduce heat to medium to ensure doneness without burning the crust.

Finish & Rest

Transfer cooked fillets to a wire rack or paper-towel-lined plate for a minute to drain. Sprinkle with chopped parsley, a light pinch of coarse sea salt and freshly ground black pepper, and squeeze fresh lemon over each fillet.

Serve

Serve the panko-Parmesan crusted grouper immediately with lemon wedges on the side. Recommended accompaniments: roasted vegetables, herbed rice, or a simple green salad.