Remove the monkfish fillets from the refrigerator 10 minutes before cooking so they reach room temperature evenly.

Pat the fillets completely dry with paper towels.

Sprinkle both sides of each fillet generously with sea salt and black pepper.

Place a large skillet over medium-high heat and let it warm for 2 minutes.

Pour 2 tablespoons of olive oil into the hot pan.

Carefully place the seasoned monkfish fillets into the hot pan and let them sear undisturbed for 4 to 5 minutes.

Using a fish spatula or tongs, gently flip each fillet and cook for another 3 to 4 minutes.

The monkfish is done when the thickest part reaches 145 degrees Fahrenheit.

While the fish rests on a plate, reduce the heat to medium and add 1 tablespoon of butter to the same pan.

Add the minced garlic and cook for just 30 seconds until fragrant.

Remove the pan from heat and stir in the remaining 2 tablespoons of butter, lemon zest, lemon juice, parsley, thyme, and red pepper flakes if using.

Return the seared monkfish fillets to the pan and gently turn them to coat with the herb butter sauce.

Transfer to serving plates and drizzle any remaining sauce over the top.