Parmesan Crusted Cod with Lemon Garlic Butter Step-by-step instructions

Before you start

Before you start, gather all your ingredients and equipment. Slice the lemons into thin wheels, mince the garlic and parsley, and grate the Parmigiano-Reggiano. Pat the cod loins dry and season them with salt and pepper.

Have your cast iron skillet hot and ready. Because the cooking time is short, having everything prepped ensures the fish sears perfectly and the spinach wilts at the right moment.

Instructions

Prepare and Coat

1. 1Prepare the lemon, garlic, and parsley
   Slice the yellow lemons into thin wheels. Mince the garlic cloves and the fresh parsley. Grate the Parmigiano-Reggiano cheese on a box grater into a fresh pile. Pat the cod loins dry with paper towels and season both sides with kosher salt and black pepper.
   Look for The lemon wheels are thin and even, the garlic and parsley are finely minced, and the cheese is freshly grated.
   Tip Grating the Parmesan yourself gives a lighter, fluffier crust that clings better to the fish.
2. 2Coat the cod in Parmesan crumbs
   Spread the grated Parmesan on a shallow plate. Press each seasoned cod loin into the cheese, turning to coat all sides. Gently pat the cheese so it adheres, then set the coated fillets on a clean plate.
   Look for Each fillet is evenly covered with a thin layer of Parmesan, with no bare spots.
   Tip Use a light hand — you want a crust, not a thick clump that might fall off during cooking.

The lemon wheels are thin, the garlic and parsley are minced, and the Parmesan is freshly grated. The cod loins are seasoned and coated with a light, even layer of cheese. The skillet is heating with butter that begins to foam.

Sear the Cod

3. 3Sear the cod in lemon garlic butter
   Heat a large cast iron skillet over medium-high heat. Add the butter and let it melt until it foams. Add the lemon wheels and minced garlic, then place the Parmesan-crusted cod loins in the pan, presentation side down. Cook without moving for 3-4 minutes until the crust is golden and crisp. Carefully flip and cook another 3-4 minutes until the fish is opaque and flakes easily with a fork.
   Look for The butter is foaming, the crust turns deep golden, and the fish turns opaque and flakes easily.
   Safe temperature 145°F (63°C) internal temperature (fish)
   Tip Resist the urge to move the fish too soon — let the crust set and brown before flipping.

The butter is foaming and the cod is sizzling gently. The Parmesan crust turns golden and crisp, and the fish becomes opaque and flakes easily when pressed. The kitchen smells of nutty butter, lemon, and garlic.

Wilt and Finish

4. 4Wilt the spinach and finish with butter and cheese
   Add the baby spinach around the fish in the same skillet. Toss it gently in the lemon garlic butter until it wilts, about 1-2 minutes. Spoon the foaming lemon garlic butter and extra grated Parmesan over the flaky cod. Serve immediately, lifting a glistening, butter-basted piece onto each plate.
   Look for The spinach is just wilted and glossy, and the extra Parmesan melts into the butter sauce.
   Tip Don't overcook the spinach — it should be bright green and tender, not mushy.

The spinach has wilted into the buttery sauce, turning glossy and tender. Extra Parmesan melts over the fish, and the foaming butter is spooned over the top. The dish is ready to serve, glistening and fragrant.

Common mistakes

One common mistake is overcrowding the pan, which lowers the temperature and steams the fish instead of searing it.

Use a large skillet and cook in batches if needed. Another mistake is moving the fish too soon — let the crust set and brown before flipping.

Overcooking is also easy with thin fillets; keep a close eye and use a thermometer. Finally, don't skip the foaming butter step — it’s what creates that rich, nutty flavor.

How to tell it’s done

The cod is done when it reaches an internal temperature of 145°F (63°C) and flakes easily with a fork. The crust should be deep golden brown and crisp, and the fish should be opaque throughout.

The spinach should be just wilted and bright green, and the butter sauce should be foamy and fragrant with lemon and garlic. Serve immediately for the best texture and flavor.

• Fish: 145°F (63°C) in the thickest part