A layer of mayonnaise on top of the cod fillets, baked with the grill, transforms into a golden, creamy crust that seals the fish and keeps it juicy. It's a simple and delicious cooking trick that turns plain fillets into an impressive dish with minimal effort. The contrast between the gratin crust and the tender cod is pure indulgence.
This recipe is so simple it's hard to believe: baked cod with a layer of mayonnaise on top that, when grilled, transforms into a golden, crispy, and flavorful crust that protects the fish from direct heat and keeps it extraordinarily juicy inside. It's the quickest recipe in this entire book (5 minutes prep, 15 minutes baking) and yet, one of the most surprising for those who try it for the first time. You don't need aioli, bechamel, or any complicated breading. Just mayonnaise.
Ingredients
- 4 desalinated cod loins (we use Extra Desalinated Cod Loin - 900g)
- 4 generous tablespoons of mayonnaise (homemade or good quality store-bought)
- 1 teaspoon Dijon mustard (optional)
- Chopped fresh herbs (parsley, chives, dill)
- Black pepper
- Olive oil
Step-by-step preparation
- Preheat oven to 200 C. Pat the cod loins dry with paper towels. Place them in a baking dish lightly greased with olive oil. If desired, add the Dijon mustard to the mayonnaise and mix well.
- Cover the top of each loin with a generous tablespoon of mayonnaise, spreading it with the back of the spoon to form an even half-centimeter layer. Do not cover the sides, only the top. Add black pepper and chopped fresh herbs over the mayonnaise.
- Bake: 12-15 minutes at 200 C. Bake until the mayonnaise is golden and puffed up, with bubbles on the surface and a color between golden and toasted. The mayonnaise completely transforms in the oven: it loses its creamy texture and becomes a crispy crust, almost like a breading but without flour.
- If the crust doesn't brown enough, activate the grill for the last 2 minutes, watching constantly. The mayonnaise goes from golden to burnt in seconds.
- Serve immediately. When you cut through the mayonnaise crust with a fork, the inside reveals incredibly juicy cod, fragrant with herbs. Serve with a crisp green salad to contrast the richness of the dish.
Our secret tip
I know: it sounds strange. Mayonnaise in the oven. But it works, and it works spectacularly. Mayonnaise is made of egg and oil, which are exactly the same ingredients as a classic breading. In the oven, the egg coagulates and forms a crispy crust while the oil bathes the cod from above, preventing it from drying out. It's pure culinary logic disguised as a quick cooking trick. Try it before you judge it.
Buy it at BacalaloExtra Desalinated Cod Loin - 900g€44.90 · Refrigerated delivery 24-48h →Discover our entire collection of desalinated cod →
Frequently Asked Questions
What kind of mayonnaise should I use?
Homemade or good quality; you can enrich it with garlic (aioli), mustard, or herbs. A full-bodied mayonnaise gratinates better without separating.
How long to bake?
Bake the cod for 8-10 min at 190 ºC and then grill the mayonnaise for 2-3 min, watching to ensure it browns without burning.
Will the mayonnaise curdle when baked?
If the grill is short and strong, it will gratinate without curdling. For more certainty, add an egg yolk or a little cheese to the mayonnaise.
