Pat the fish fillets very dry with paper towels. Season both sides evenly with the kosher salt and freshly ground black pepper.

Place the flour in a shallow dish and lightly coat each fillet on both sides. Shake off the excess so the fish has a thin coating rather than a thick, gummy layer.

Heat the oil in a large skillet over medium to medium-high heat. Add the fish without crowding the pan and cook for approximately 3 to 4 minutes per side, depending on thickness, until golden and flaky.

Transfer the cooked fish to a plate once the thickest part reaches 145°F (63°C) and the flesh is opaque. If the skillet is too small for all four fillets, cook in batches so the fish browns instead of steaming.

Reduce the heat to medium-low and add the butter and minced garlic to the skillet. Cook for about 30 seconds, stirring gently, just until the garlic becomes fragrant without turning dark.

Add the lemon juice and optional lemon zest, then stir while scraping up the browned bits from the bottom of the skillet. These browned bits add savory flavor to the quick sauce.

Return the fish briefly to the skillet and spoon the lemon butter sauce over the fillets. Sprinkle with parsley and serve immediately with lemon wedges.