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

Before you start

Before cooking, slice the lemon, mince the garlic and parsley, and grate the Parmigiano Reggiano. Pat the cod dry and season it with salt and pepper. Have the butter ready and the spinach washed.

Because the cooking goes quickly, having everything prepped and within reach makes the process smooth. The skillet should be hot before the butter goes in, so give it a few minutes to heat up.

Instructions

Prep and Coat

1. 1Prep the ingredients
   Slice the lemon into thin wheels. Mince the garlic and parsley. Grate the Parmigiano Reggiano on the fine holes of a box grater into a shallow dish. Pat the cod loins dry and season both sides with kosher salt and pepper.
   Look for The lemon wheels are uniform, garlic and parsley are minced, and the cheese is finely grated.
   Tip Use a microplane or the fine side of the box grater for the fluffiest Parmesan texture.
2. 2Coat the cod in Parmesan crumbs
   Press each seasoned cod loin into the grated Parmesan, turning to coat all sides. The cheese forms a craggy crust that will crisp in the butter.
   Look for Each piece is evenly coated with a thin, shaggy layer of cheese.
   Tip Let the coated fish rest for a few minutes so the cheese adheres better.

The lemon wheels are thin and even, the garlic and parsley are minced, and the cheese is finely grated.

The cod loins are seasoned and coated with a shaggy layer of Parmesan. The skillet is heating, and the butter is ready to go.

Sear and Wilt

3. 3Sear the cod in lemon garlic butter
   Place a large cast iron skillet over medium-high heat and add the butter. When it foams, add the garlic and lemon wheels. Cook for 30 seconds until fragrant. Gently lay the cod in the pan, presentation side down. Cook undisturbed for 3 to 4 minutes, until the crust is golden and releases easily.
   Look for The butter is foaming, the garlic smells nutty, and the fish releases from the pan.
   Tip If the fish sticks, give it a few more seconds — it will release when the crust is set.
4. 4Flip and finish cooking
   Carefully flip each piece with a fish spatula. Cook for another 3 to 4 minutes, basting with the foaming butter, until the fish is opaque and flakes easily. The internal temperature should reach 145°F (63°C).
   Look for The second side is golden, and the fish flakes when pressed with a fork.
   Safe temperature 145°F (63°C) internal temperature (fish)
   Tip Use a digital thermometer to check the thickest part of the loin.
5. 5Wilt the spinach around the fish
   Add the baby spinach to the skillet around the cod. Toss gently in the buttery pan juices for 1 to 2 minutes, until just wilted but still bright green.
   Look for The spinach is reduced in volume and glistening with butter.
   Tip Don't overcook — the spinach should keep a little texture.

The butter is foaming and fragrant with garlic. The cod is golden on both sides and flakes easily. The spinach is just wilted and glistening with butter. The pan juices are bubbling and smell bright and savory.

Finish and Serve

6. 6Spoon the butter over the fish
   Tilt the skillet and spoon the foaming lemon garlic butter over the cod several times. The fish soaks up the bright, savory sauce.
   Look for The butter is bubbling and the fish looks glossy.
   Tip Use a large spoon to catch the lemon slices and garlic bits.
7. 7Finish with Parmesan and serve
   Sprinkle the extra grated Parmigiano Reggiano over the fish and spinach. Lift a piece onto a plate with the spinach and lemon wheels, spooning any remaining butter over the top. Serve hot.
   Look for The cheese melts slightly over the hot fish, and the butter pools on the plate.
   Tip Serve immediately — the crust is best when just seared.

The fish is glossy from the butter baste, and the extra Parmesan is melting over the top. The spinach is tender and coated. The lemon wheels are caramelized at the edges. Everything is ready to plate and serve immediately.

Common mistakes

One common mistake is overcrowding the pan — if the pieces touch, they steam instead of searing. Cook in batches if needed. Another is flipping too early; the crust needs time to set and release from the pan.

Also, avoid overcooking the spinach; it should wilt quickly and keep its color. Finally, don't skip the final basting — it adds moisture and flavor.

How to tell it’s done

The cod is done when it reaches 145°F (63°C) in the thickest part and flakes easily with a fork. The crust should be deep golden brown and crisp.

The spinach should be wilted but still bright green. The butter will be foamy and fragrant with lemon and garlic. If the fish resists flaking, cook for another minute or two.

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