James Martin Cod Recipes: Buttery Baked Cod with Leeks

This British-style baked cod pairs mild, flaky fish with creamy leeks and a crisp parsley breadcrumb topping, and it is served straight from the oven with potatoes or greens. For anyone searching James Martin cod recipes, this is an original home-cooking recipe, not a claim to reproduce a particular chef’s published dish.

Ingredients

4 skinless cod fillets, about 6 oz (170 g) each, thawed if frozen and patted dry
1 medium leek, about 5 oz (150 g), white and pale-green parts only
1 tbsp (15 ml) olive oil
2 tbsp (28 g) unsalted butter, divided
½ cup (120 ml) heavy cream
½ cup (120 ml) fish stock or low-sodium vegetable stock
1 tsp (5 ml) Dijon mustard
1 tsp (2 g) finely grated lemon zest
2 tbsp (30 ml) fresh lemon juice, divided
½ tsp (3 g) fine salt, plus more to taste
¼ tsp (0.5 g) freshly ground black pepper
1¼ cups (60 g) panko breadcrumbs
¼ cup (15 g) finely chopped fresh parsley
1 tbsp (15 ml) water, if needed to loosen the sauce

Instructions

Heat the oven and prepare the dish. Set a rack in the middle of the oven and preheat it to 400°F (200°C). Lightly oil a shallow baking dish large enough to hold the cod in one layer. If the fish was frozen, thaw it fully in the refrigerator, then blot it well with paper towels; excess surface water can thin the sauce and prevent the topping from crisping.
Slice and soften the leek. Cut the leek lengthwise and rinse between its layers to remove any grit. Slice it thinly. Melt 1 tablespoon (14 g) of the butter with the olive oil in a skillet over medium heat. Add the leek and cook for 5 to 7 minutes, stirring, until softened but not browned. If the pan looks dry, add a teaspoon of water rather than turning up the heat. Transfer the leek to the baking dish and spread it evenly.
Make the creamy base. In a bowl, whisk together the heavy cream, stock, Dijon mustard, lemon zest, 1 tablespoon (15 ml) of the lemon juice, salt, and pepper. Taste a small spoonful and adjust the seasoning, bearing in mind that stock can already be salty. Pour the mixture over the leeks. The sauce will look fairly loose before baking; it thickens as it cooks and mingles with the fish.
Add the cod and crumb topping. Arrange the fillets over the leek mixture with a little space between them. Turn them once in the sauce so the undersides are coated, then leave the top surfaces clear for the breadcrumbs. Combine the panko and parsley in a small bowl. Melt the remaining 1 tablespoon (14 g) butter and stir it through the crumbs until they are lightly moistened. Scatter the mixture evenly over the fish. Avoid pressing it down, which can make the topping dense rather than crisp.
Bake until the fish is done. Bake uncovered for 14 to 18 minutes, depending on the thickness of the fillets. Check the thickest part of a fillet with a food thermometer: the USDA FSIS safe minimum internal temperature for fish is 145°F (63°C). At that temperature, cod should be opaque and separate into moist flakes when gently tested with a fork. If the crumbs need more color once the fish is safely cooked, broil briefly, watching constantly so they do not burn.
Finish and serve. Let the dish stand for 2 minutes, then drizzle over the remaining 1 tablespoon (15 ml) lemon juice. Taste the sauce and add a little salt or pepper if needed. Spoon some leek sauce onto each plate, set a cod fillet on top, and include plenty of the golden crumbs. Serve while hot.

Tips

Choose evenly sized portions. Fillets of similar thickness finish at roughly the same time. If one piece is notably thinner, check it early and remove it as soon as it reaches 145°F (63°C), leaving thicker portions in the oven until they are ready.
Rinse the leek carefully. Soil can hide between the layers, so split the leek lengthwise and rinse it before slicing. Use only the white and tender pale-green section here; the dark-green tops are tougher but can be saved for stock.
Keep the topping dry enough to crisp. Panko gives a light, crunchy finish. Regular dry breadcrumbs work too, though the crust will be finer and less airy. Fresh, soft bread crumbs absorb more butter and may form a heavier layer.
Season the sauce thoughtfully. Use low-sodium stock when possible and taste before adding extra salt. If the sauce seems especially thick after baking, stir in a spoonful of warm water or stock at the table rather than baking the fish longer.

Serving Suggestions

The creamy leek sauce makes this cod especially good with something that can catch it. Serve it with boiled or mashed potatoes, buttered new potatoes, or plain rice. For a more substantial plate, roasted potatoes are a good match for the crunchy topping, while crusty bread is useful for mopping up sauce.

Add a green vegetable to balance the richness: steamed green beans, peas, broccoli, or tenderstem broccoli all work well. A lightly dressed salad of crisp leaves and cucumber is another option, particularly if the rest of the meal is hearty. Keep extra lemon wedges on the table so each person can brighten their portion to taste. For a dinner party, bake and serve the dish in its cooking dish, taking care when carrying the hot sauce to the table.

Variations

Use another firm white fish. Haddock, pollock, or hake can stand in for cod in equal-sized portions. Their flavor and texture differ slightly, but the creamy leek base and crumb topping suit all three. Check the thickest piece for 145°F (63°C), since cooking time depends more on thickness than on the fish’s name.

Make the topping with ordinary breadcrumbs. If panko is not available, use the same volume of plain dry breadcrumbs. For a savory variation, mix in 2 tablespoons (10 g) finely grated Parmesan; this adds saltiness, so taste the sauce before seasoning it further. Chopped chives can replace some or all of the parsley.

Lighten or enrich the sauce. Half-and-half can replace the heavy cream for a less rich result, although the sauce will be thinner. For a thicker, more luxurious sauce, use ⅔ cup (160 ml) cream and reduce the stock to ⅓ cup (80 ml). Do not use very low-fat milk as a direct replacement, because it is more likely to look watery in the oven.

Add vegetables to the baking dish. A handful of thawed peas can be stirred into the leek mixture before adding the fish. Thinly sliced fennel can be softened with the leek for a gentle anise note. Avoid adding a large amount of raw, watery vegetables, which can release liquid and dilute the sauce.

Storage and Reheating

Refrigerate leftovers within 2 hours of cooking in a covered, shallow container. Keep the fish and sauce together, and use the leftovers within 3 to 4 days. The breadcrumb crust softens as it sits, so it will not be quite as crisp the next day. For longer storage, freeze cooled portions in an airtight freezer-safe container; use within about 2 months for best texture. Thaw frozen portions overnight in the refrigerator before reheating.

Reheat only the portion you plan to eat. Cover it loosely and warm it in a 325°F (165°C) oven until hot throughout, adding a spoonful of water or stock if the sauce has thickened. Check that leftovers reach 165°F (74°C), the USDA FSIS reheating temperature. A microwave also works: use medium power in short bursts, with the dish covered, and check the center temperature. Gentle heating helps prevent the cod from drying out, but do not rely on the appearance of the sauce alone to judge whether it is hot enough.

Frequently Asked Questions

Can I use frozen cod?

Yes. Thaw it completely in the refrigerator before cooking and pat it dry. Baking fish while still frozen can release extra water, changing the consistency of the sauce and making the cooking time less predictable. Do not thaw cod on the counter.

How can I tell when cod is cooked?

Use an instant-read food thermometer in the thickest part of the fillet and cook it to 145°F (63°C). The flesh should also look opaque and flake when gently pressed with a fork, but those visual signs are less precise than checking the temperature.

Can I prepare the dish ahead?

You can wash and slice the leek, chop the parsley, and mix the breadcrumb topping earlier in the day; keep them covered and refrigerated separately. For the best texture, assemble the sauce and fish shortly before baking. If a cold dish goes into the oven, it may need extra time, so rely on the thermometer rather than adding a fixed number of minutes.

What can I use instead of fish stock?

Low-sodium vegetable stock is an easy substitute and keeps the sauce mild. Water also works, although the finished sauce will have less savory depth. Avoid strongly flavored stock, which can overwhelm the delicate cod and leek.

Why did my baked cod turn watery?

Common causes include fish that was not thawed or dried properly, a very watery vegetable addition, or baking the fish directly from frozen. Drain thawed fish well, blot it dry, and use the quantities of cream and stock listed. Also avoid extending the cooking time after the cod reaches its safe temperature, since overcooking can make the fish release more liquid and become dry.

More recipes to cook

Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

Spotted an error? Tell us and we will correct it (corrections policy).