Searing Secrets: Mastering The Art Of Fish In Cast Iron

Searing fish in a cast-iron pan is a classic method for cooking fish that is used in restaurants. The result is a piece of fish with a crisp exterior and a juicy and flavourful interior. It's so easy to do that you can simply prepare the fish yourself at home.

To get the perfect sear, you'll need to use a well-seasoned cast-iron skillet and heat the pan on high. You'll also want to use a little olive oil or another oil with a high smoke point, like avocado or refined safflower oil.

If you're using a fish with skin, place the skin side down first and consider pre-scoring the skin to prevent curling. If your fish doesn't have skin, just sear the side the skin used to be on first.

Choosing the right fish

Firstly, it is important to consider the size of the fish. Smaller fish, such as sardines, tend to have a higher risk of overcooking or falling apart during the searing process. Therefore, it is recommended to opt for larger fish with thicker fillets, such as salmon, tuna, or mahi-mahi. These fish have a more substantial size and texture, making them ideal for searing.

Secondly, the type of fish skin plays a crucial role in the searing process. Some fish, like triggerfish, sturgeon, and swordfish, have thick or rubbery skin that does not crisp well. On the other hand, fish such as bass, perch, salmon, flounder, snapper, and rock cod have skin that crisps nicely and adds flavour to the dish. Scaling the fish properly before cooking is essential to ensure the skin cooks evenly.

Lastly, the oil or fat used for searing is an important consideration. Regular butter should be avoided as it burns easily at high temperatures. Instead, opt for oils with high smoke points, such as avocado oil, refined safflower oil, canola oil, or clarified butter. These oils can withstand higher temperatures without burning, ensuring that your fish is cooked properly without any unpleasant bitterness.

In summary, when choosing the right fish for searing in a cast-iron pan, opt for larger fish with thicker fillets and skin that crisps well. Additionally, remember to use oils with high smoke points to prevent burning and achieve the perfect sear.

Preparing the fish

The first step in preparing your fish for searing is to decide whether you want to cook it with or without the skin. If you choose to cook it with the skin, make sure the fish has been properly descaled. If you don't like the skin, simply remove it before cooking.

Next, take your fish out of the fridge 20-30 minutes before cooking and sprinkle both sides with salt. This will help to bring the fish to room temperature and ensure even cooking.

Now, use a butter knife to gently scrape down the skin side of the fillet to remove any excess moisture. If you are using a skinless fillet, you can skip this step. Then, pat the entire fillet dry with paper towels.

When you are ready to start cooking, set a cast-iron pan over high heat until it is very hot. While the pan is heating up, pour your chosen oil into the centre of the pan and swirl it around to coat the entire bottom. Good choices for searing oil include avocado oil and refined safflower oil, which have smoke points above 500°F. You could also use canola oil, rice bran oil, refined peanut oil, beef tallow, or clarified butter.

Cooking the fish

Once your pan is hot and your fish is prepared, it's time to start cooking! Lay the fillet with the skin facing down (or the side where the skin used to be) and give the pan a firm jiggle to prevent the fish from sticking.

Immediately reduce the heat to medium-high (or medium if your fillet is very thick). Use a metal spatula to firmly press down on the fillet for 30-60 seconds. This will help ensure even cooking and prevent the fish from curling.

Now, stop touching the fish and leave it undisturbed to cook for another minute or so. The cooking time will vary depending on the type and thickness of your fish, so keep an eye on it. For most fish, you'll want to spend 2/3 of the cooking time on the skin side to get that crispy finish.

For thicker fillets, keep an eye on the edge of the fish where the meat meets the pan. You'll see the colour change moving up the side of the fillet as it cooks. When there is a solid ring of golden colour around the outside, it's time to flip the fish.

A good test to see if your fish is ready to flip is to give the pan a firm shake. If your fish moves, it's ready to be flipped using a metal spatula. Note that the fish should not be completely stuck to the pan, but a few spots may be sticking, and you can use the spatula to gently unstick it.

If the fish is legitimately stuck to the pan, be patient and give it a little more time to cook. It will release itself from the pan when it is perfectly seared.

Once you've flipped your fish, it will only need to cook for another minute or so. Typically, you can turn off the heat and let the residual heat finish cooking the fish.

Finishing touches

To finish your dish, add a tablespoon of butter to the pan and swirl it around so it melts quickly. Tip the pan and use a spoon to baste the fish with the butter.

When the fish is done, serve it immediately. Unlike other meats, seared fish is best served right away and doesn't need time to rest. Serve your fish with the skin side facing up to show off that crispy, golden finish.

Enjoy your perfectly seared fish!

Heating the pan

While the pan is heating up, prepare your fish fillets. If your fillets have skin, use a butter knife to gently scrape down the skin side of the fillet to remove any excess moisture. Then, pat the whole fillet dry with a paper towel. If you are using skinless fillets, you can skip the scraping step and simply pat the fillets dry.

Once your pan is hot, add your oil of choice. You'll want to use an oil with a high smoke point, such as avocado oil or refined safflower oil. Other options include canola oil, rice bran oil, refined peanut oil, or refined sunflower oil. Pour about 2 tablespoons of oil into the centre of the pan and swirl it around to coat the entire bottom of the pan.

Let the oil heat up, but be careful not to let it smoke. If it starts to smoke, remove the pan from the heat until it stops.

Now it's time to add your fish to the pan. Lay the fillets with the skin facing down, or the side where the skin used to be. Give the pan a firm jiggle to prevent the fish from sticking. If your fillets have skin, you may also want to pre-score the skin to prevent curling.

Immediately reduce the heat to medium-high or medium, depending on the thickness of your fillets. You want the oil to sizzle like bacon. Use a metal spatula to firmly press down on each fillet for 30 to 60 seconds. This will help ensure even cooking and prevent the fillets from curling.

Adding the fish

Now that your cast-iron pan is hot, it's time to add the fish. If your fish has skin, place it skin-side down first. Give the pan a firm jiggle to prevent the fish from sticking. If your fish doesn't have skin, lay it down on the side where the skin used to be.

If your fish has skin, you can pre-score it to prevent curling, but you can also remedy this by gently pressing down on the fish with a fish spatula. Using a bacon press or a metal spatula, press down on each fillet for 30 to 60 seconds. Fish tends to arc when it's seared, and you want the skin side to brown evenly.

If you are cooking multiple fillets at once, make sure they aren't too close to one another in the pan.

Turn the heat down to medium-high or medium if your fillet is thick. You want the fish to sizzle like bacon.

Cooking the Fish

Stop touching the fish and leave it completely undisturbed for at least a minute. The cooking time will vary depending on the type of fish, ranging from a minute to 8 or 9 minutes. You'll want the fish to spend 2/3 of the cooking time on the skin side, as this is what crisps the skin. The thicker the fillet, the longer the cooking time and the lower the heat.

When to Flip

Whether or not you need to flip your fish depends on its thickness. Thinner fillets can be cooked without flipping by spooning the hot oil over the top. For thicker fillets, keep an eye on the edge of the fish where the meat meets the pan. You'll see the cooked portion climb up the sides; when there is a solid ring of browned goodness around the sides, it's time to flip.

A good test is to shake the pan—if the fillet moves, you can flip it. Use a metal spatula to flip the fish. Be prepared to scrape the skin off the bottom, as it may be stuck to the pan. If it's stuck, be patient and let it keep cooking. It will release when the sear is perfect.

Finishing Cooking

Once you've flipped the fish (if needed), you'll only need to cook it for another minute or so. Typically, you can turn off the heat and let the residual heat finish cooking the fish.

Basting

Add a tablespoon of butter to the pan and swirl it so it melts quickly. Tip the pan and use a spoon to baste the fish with the butter.

Serving

When the fish is done, serve it immediately. Unlike other meats, seared fish doesn't benefit from resting. Serve the fish with the skin side facing up, and if you're using a sauce, pour it over or under the fish, not on top of the crispy skin.

Cooking the fish

Now that you have your cast-iron pan, it's time to cook the fish! Here's a step-by-step guide to achieving that perfect sear:

Prepare the Fish

• If your fish has skin, use a sharp knife to score the skin every two inches across the fillet. Be careful not to cut too deep—you just want to score the skin, not the flesh.
• Pat the fish dry on both sides with a paper towel. Removing excess moisture will help prevent the fish from sticking to the pan.
• Season the fish generously with salt and pepper on both sides. You can also try other seasonings like paprika or dried herbs if you want to add extra flavour.

Heat the Pan

• Place your cast-iron pan on the stove and turn the heat to high. Cast iron performs best when it's scorching hot, so don't be shy with the heat.
• While the pan is heating up, choose your oil. Avocado oil, olive oil, grapeseed oil, canola oil, refined safflower oil, and clarified butter are all great options with high smoke points.
• Once the pan is hot, add about 2-3 tablespoons of your chosen oil to the centre of the pan and swirl it around to coat the entire cooking surface evenly.

Cook the Fish

• When the oil is hot, it's time to add the fish. Place the fillets in the pan, skin-side down if they have skin. If the fillets have skin, give the pan a gentle jiggle to prevent the fish from sticking.
• Immediately reduce the heat to medium-high or medium, depending on the thickness of your fillets. You want the oil to sizzle, but be careful not to let it smoke.
• Use a metal spatula or a bacon press to firmly press down on each fillet for 30-60 seconds. This helps prevent the fish from curling and ensures even cooking.
• Let the fish cook undisturbed for at least a minute, possibly longer depending on the type and thickness of your fillets. For thinner fillets, you may not need to flip them at all.
• For thicker fillets, keep an eye on the edge of the fish where the flesh meets the pan. When you see a solid ring of golden colour forming around the edges, it's time to flip.
• To check if your fish is ready to flip, give the pan a gentle shake. If the fillet moves freely, it's ready to be flipped. Use a metal spatula to carefully flip the fish, being careful not to break the fillet.
• Once flipped, cook the fish for another minute or so. For thicker fillets, you may need to cook them a bit longer, around 3-5 minutes.
• To test for doneness, gently press down on the fish with your spatula. If it flakes easily, it's likely cooked through. You can also use an instant-read thermometer to check the internal temperature, which should be around 120°F to 125°F for medium-rare to medium doneness.

Finishing Touches

• Once your fish is cooked to your desired level of doneness, transfer it to a serving plate, skin-side up. This will help keep the crispy skin from getting soggy.
• If you're using a sauce or garnish, it's best to serve it on the side or underneath the fish to preserve the crispy skin. A squeeze of lemon or lime juice is a great way to add a burst of freshness to your dish.
• Serve the fish immediately. Seared fish is best enjoyed straight out of the pan to preserve the crispy texture.

Frequently asked questions