Gratin cod is one of those dishes that always work: they look good, impress, and are prepared in less than 30 minutes in the oven. We present 5 gratin cod recipes (with béchamel, with aioli, with tomato, with vegetables, and with cheese) with precise instructions to make them perfect on your first try.
Why gratin cod always works
Updated March 2026. Since 1990, we have hand-selected every product. This guide reflects that experience.
Gratin is one of the most rewarding cooking techniques. You combine intense heat from above (grill) with a protective layer (béchamel, cheese, aioli) that creates a golden crust while keeping the inside juicy. Applied to cod, this technique solves the main problem with baked fish: its tendency to dry out.
The gratin layer acts as a thermal shield. The cod cooks gently under this covering, staying moist and absorbing flavor. The result is a juicy fish with a crispy, golden surface.
Furthermore, gratin cod is a visually impressive dish that doesn't require advanced skills. It comes out of the oven dish with that appetizing golden hue that invites you to eat. Few dishes offer so much reward with so little effort.
What cod to choose for gratin
For gratin, you need medium-thickness pieces (2-3 cm), preferably loin or center cuts. Pieces that are too thin dry out before the gratin can brown. Those that are too thick take too long to cook, and the gratin burns.
- Ideal: center loin, 2-3 cm thick, desalted, with or without skin
- Alternative: desalted cod supremes, regular cut
- Avoid: tail (falls apart), flakes (cannot be gratinated in one piece)
If the cod has skin, always place it skin-side down. The skin protects the base and the gratin layer protects the top.
Recipe 1: Gratin cod with béchamel
Ingredients (4 servings)
- 4 desalted cod loins (180-200g each)
- 50g butter
- 50g flour
- 500ml whole milk
- Grated nutmeg
- 50g grated cheese (Emmental or Gruyère)
- Salt and white pepper
Preparation
Prepare the béchamel: melt the butter over medium heat, add the flour and stir for 2 minutes (roux). Gradually add the milk, stirring constantly, until you get a thick, lump-free sauce. Season with nutmeg, salt (sparingly, as the cod is already salty) and pepper.
Place the cod loins in a greased baking dish. Cover with béchamel sauce and sprinkle with grated cheese. Bake at 200 °C for 15-18 minutes, the last 3 minutes with the grill activated to brown the surface.
Result: an infallible classic. The béchamel envelops the cod in creaminess, and the gratinated cheese provides the crispy crust. Perfect for family dinners.
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Recipe 2: Gratin cod with aioli
Ingredients (4 servings)
- 4 desalted cod loins
- 4 generous tablespoons of aioli (homemade or good quality)
- Sweet paprika (optional)
- Fresh parsley
Preparation
Place the cod loins in an ovenproof dish. Cover each loin with a generous layer of aioli (about 1.5 cm thick). Sprinkle with sweet paprika if you want some color.
Bake at 200 °C for 12-15 minutes. The aioli will puff up, brown, and create a spectacular crust. The inside of the cod will be juicy with a mild garlic flavor.
Result: the fastest and possibly the most delicious version. The aioli transforms in the oven: it loses density, becomes airy, and forms a crust that is crispy on the outside and creamy on the inside. It's addictive.
Tip: If the aioli is homemade (just garlic, oil, and salt, no egg), the gratin will be lighter. With mayonnaise-type aioli (with egg), it will be denser and more golden.
Recipe 3: Gratin cod with tomato and cheese
Ingredients (4 servings)
- 4 desalted cod loins
- 400 g crushed natural tomatoes
- 1 sautéed onion
- 2 cloves garlic
- 150 g fresh mozzarella
- Dried oregano
- Extra virgin olive oil
Preparation
Prepare a quick sofrito: sauté the onion with the garlic, add the tomato, and cook for 10 minutes until it thickens. Season with oregano, salt, and pepper.
Spread half of the sofrito in a baking dish. Place the cod loins on top. Cover with the remaining sofrito. Top with slices of fresh mozzarella.
Bake at 200 °C for 18-20 minutes. The mozzarella will melt, brown, and the tomato will bubble. Let it rest for 5 minutes before serving.
Result: Italian inspiration with Mediterranean produce. The tomato and mozzarella work incredibly well with cod. It is one of the most popular versions among children and those who are not big fans of fish.
Recipe 4: Gratin cod with vegetables
Ingredients (4 servings)
- 4 desalted cod loins
- 1 zucchini
- 1 red pepper
- 1 onion
- 200 g mushrooms
- 100 ml cooking cream
- 50 g grated Parmesan cheese
- Olive oil, salt, pepper, Herbes de Provence
Preparation
Cut all the vegetables into julienne strips or thin slices. Sauté them in olive oil over high heat for 5-7 minutes: they should be tender but still have some texture. Season with Herbes de Provence.
Place the cod in the baking dish. Cover with the sautéed vegetables. Mix the cream with the Parmesan and pour over the top.
Bake at 190 °C for 20 minutes. Activate the grill for the last 3 minutes.
Result: a complete meal in one dish. The vegetables provide flavor and garnish, while the cream with Parmesan creates the gratin. Ideal for weekday meals when you want something hearty without fuss.
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Recipe 5: Gratin cod with cream cheese
Ingredients (4 servings)
- 4 desalted cod loins
- 200 g cream cheese (Philadelphia type)
- 50 g blue cheese (Cabrales, Roquefort)
- 2 tablespoons milk
- Fresh chopped chives
- Black pepper
Preparation
Mix the cream cheese with the crumbled blue cheese and milk until a homogeneous cream is obtained. Season with pepper (do not add salt: blue cheese and cod are already salty).
Place the cod in the baking dish. Cover with the cheese cream. Bake at 190 °C for 15-18 minutes until the surface is golden and bubbly.
Serve with chopped chives on top.
Result: the most powerful version in terms of flavor. Blue cheese elevates cod to another level. Not suitable for timid palates, but spectacular for those who appreciate intense flavors. It pairs very well with a full-bodied white wine.
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Comparison table of the 5 recipes
| Recipe | Difficulty | Total time | Flavor intensity | Ideal for |
|---|---|---|---|---|
| With béchamel | Medium | 35 min | Mild | Family, children |
| With aioli | Easy | 20 min | Medium | Quick dinners |
| With tomato and cheese | Easy | 35 min | Medium | Children, daily meals |
| With vegetables | Medium | 40 min | Medium | Complete single dish |
| With cream cheese | Easy | 25 min | Intense | Special dinners, adults |
Tips for a perfect gratin
Dry the cod well. Before placing it in the dish, dry it with kitchen paper. Surface moisture prevents the gratin layer from adhering well and generates steam that can make the crust soft.
Always preheat the oven. The cod should go into an already hot oven (190-200 °C). If the oven is cold, the fish cooks slowly and dries out before the gratin forms.
The grill at the end, not at the beginning. First cook with conventional heat (top and bottom heat) so that the cod cooks evenly. For the last 3-4 minutes, activate only the grill to brown the surface.
Do not cover the dish. The gratin needs direct heat on the surface. If you cover it with aluminum foil, you will have steamed cod, not gratin.
Let rest for 5 minutes. When it comes out of the oven, the gratin layer is extremely hot and liquid. Let it set for 5 minutes before serving: it compacts and develops better flavor.
Frequently asked questions
Can frozen cod be gratinated directly?
It is not recommended. Frozen cod releases water when thawing in the oven, which prevents proper gratin. Always thaw in the refrigerator 24 hours before and dry thoroughly before gratinating.
How long does it take to gratin cod in the oven?
Between 15 and 20 minutes at 190-200 °C, depending on the thickness of the cod and the gratin layer. The last 3 minutes with the grill to brown. The cod is ready when the flakes separate when pressed with a fork.
Can I prepare gratin cod and bake it later?
Yes. You can assemble the dish (cod + topping) and store it covered in the refrigerator for up to 6 hours. Take it out 15 minutes before baking so it's not completely cold. Add an extra 3-5 minutes to the baking time.
What cheese is best for gratin cod?
It depends on the recipe. For béchamel: Emmental or Gruyère (melt well and brown). For tomato: mozzarella (stretches and bubbles). For intensity: Parmesan (strong flavor) or blue cheese. Avoid soft cheeses like Burgos, which do not gratinate.
Is gratin cod healthy?
Cod itself is a lean fish, rich in protein and omega-3. The gratin adds calories due to the béchamel, cheese, or aioli. A serving of gratin cod with béchamel provides about 350-400 kcal. With aioli, slightly less. It is a balanced dish if accompanied by salad or vegetables.
Can gratin cod be made without an oven?
Yes, with a kitchen blowtorch. Cook the cod in a pan or steam it, place the topping, and brown with a blowtorch. It's not exactly the same (the oven also cooks with enveloping heat), but it works for kitchens without an oven.
Gratin Cod with Aioli: Complete Step-by-Step Recipe
Gratin cod with aioli is the most requested recipe at Mercat del Ninot. The reason is simple: in 20 minutes you have a spectacular dish with only 2 main ingredients. Here is the detailed version with all the tricks.
Ingredients for 4 people
- 4 desalted cod loins of 180-200 g (2.5-3 cm thick)
- 200 g homemade aioli (see recipe below)
- Sweet paprika from La Vera
- Fresh chopped parsley
- Extra virgin olive oil
Homemade aioli (the version that makes all the difference)
- 4 large garlic cloves
- 1 egg at room temperature
- 250 ml mild extra virgin olive oil
- Juice of half a lemon
- A pinch of salt
In a blender cup, place the peeled garlic, egg, lemon, and salt. Add the oil. Insert the hand blender to the bottom without moving and turn it on. When it starts to emulsify, slowly lift it. In 30 seconds, you'll have perfect aioli.
Step-by-step gratin preparation
- Preheat the oven to 200 °C with top and bottom heat.
- Dry the cod loins with absorbent paper. Moisture prevents the aioli from adhering.
- Grease the baking dish with a drizzle of olive oil.
- Place the loins skin-side down (if they have skin).
- Cover each loin with a generous layer of aioli (approximately 1.5 cm thick). Do not skimp: the aioli is the key to the gratin.
- Sprinkle La Vera paprika over the top (it adds color and a subtle smoky touch).
- Bake for 12-15 minutes at 200 °C. The aioli will puff up, brown, and create a spectacular crust.
- Grill option: If you want a crispier crust, activate the grill for the last 2 minutes. Watch constantly — there are only 30 seconds between perfectly golden and burnt.
- Rest for 3 minutes before serving. Sprinkle with fresh parsley.
Result: a crispy, airy alioli crust on the outside, creamy on the inside. The cod remains juicy because the alioli acts as a thermal shield. It's probably the most impressive recipe you can make in 20 minutes.
Baked Gratin Cod with Potatoes
Baked gratin cod with potatoes is the most complete version: a single dish, with no need for additional side dishes. The potatoes absorb the juices from the cod and the topping, becoming tender and flavorful.
Ingredients (4 servings)
- 4 desalted cod loins (180-200 g)
- 600 g potatoes (Monalisa or similar, firm texture)
- 1 large onion, thinly julienned
- 3 cloves garlic, sliced
- 150 ml cooking cream
- 80 g grated Emmental or Gruyère cheese
- Extra virgin olive oil
- Salt, black pepper, parsley
- Optional: 100 ml white wine
Step-by-step preparation
- Peel and slice the potatoes thinly (3-4 mm). If you have a mandoline, use it.
- Sauté the onion and garlic in oil over low heat for 10 minutes until transparent.
- Assemble the dish: spread the potato slices on the base, slightly overlapping. Season with salt and pepper. Distribute the sautéed onion on top.
- Pour in the white wine (if using) and 100 ml of water. This creates steam that cooks the potatoes from below.
- Bake the potatoes alone at 190 °C for 20 minutes. They should be almost tender.
- Place the cod on top of the pre-cooked potatoes.
- Mix the cream with half of the cheese and pour over the cod.
- Sprinkle the remaining cheese on top.
- Bake for another 15-18 minutes at 200 °C. The last 3 minutes with the grill to brown.
- Rest for 5 minutes. Sprinkle with fresh parsley and serve in the same dish.
Tip: pre-cooking the potatoes for 20 minutes without the cod is essential. If you put everything in at once, either the potatoes will be raw or the cod will be dry. Don't skip this step.
Conclusions
Gratin cod is the answer to the question "what can I make for dinner that is delicious, easy, and looks good?". With five different recipes, you have options for the whole week without repeating: béchamel for a classic Monday, alioli for a quick Tuesday, tomato for a family Wednesday, vegetables for a complete Thursday, and cream cheese for a special Friday.
The common denominator for all five: good cod, a hot oven, and don't overcook. With these three rules, any of these recipes will work the first time.
Marc González Sáez has been working with cod since 1990 in Mercat del Ninot, Barcelona. At Bacalalo.com we select cod cuts with the perfect thickness for gratin: not so thin that they dry out, nor so thick that they don't cook in time.
