Bacalhau à Gomes de Sá: A Traditional Portuguese Recipe

Bacalhau à Gomes de Sá is a classic dish from Porto, Portugal, made with salt cod, potatoes, onions, olive oil, hard-cooked eggs, and olives. The cod needs time to desalinate, but once it is ready, gentle cooking and a short bake bring the ingredients together in a savory, tender casserole; family and regional versions vary in their details.

Ingredients

1 lb (450 g) dried salt cod, skin-on or skinless, cut into large pieces
About 8 cups (1.9 L) cold water for the initial soak, plus fresh water for changes
2 lb (900 g) waxy potatoes, such as Yukon Gold, scrubbed
3 medium yellow onions, about 1 lb (450 g), thinly sliced
4 garlic cloves, about 12 g, thinly sliced
½ cup (120 ml) extra-virgin olive oil, divided
2 bay leaves
½ teaspoon (1 g) freshly ground black pepper, or to taste
4 large eggs, for hard cooking and serving
½ cup (75 g) pitted black olives, preferably Portuguese or another briny variety
¼ cup (15 g) chopped fresh flat-leaf parsley
1 tablespoon (15 ml) olive oil, for the baking dish, if needed
Lemon wedges, optional, for serving

Instructions

Desalt the cod, 24 hours ahead. Rinse the salt cod under cold running water to remove loose surface salt. Put it in a large nonreactive bowl, cover with about 8 cups (1.9 L) cold water, and refrigerate. After 8 hours, pour off the water, rinse the bowl, and cover the cod with fresh cold water. Repeat twice more, changing the water about every 8 hours. Keep the fish refrigerated throughout this process. If the pieces are unusually thick or still taste intensely salty after 24 hours, continue soaking for another 8 to 12 hours, changing the water once; desalting time depends on the cut and thickness.
Prepare the potatoes and eggs. Drain the cod and pat it dry. Put the whole potatoes in a large pot, cover with cold water, and bring to a simmer. Cook for about 18 to 22 minutes, until a knife enters with slight resistance rather than the potatoes falling apart. Meanwhile, put the eggs in a saucepan, cover with water, bring to a boil, and cook for 9 to 10 minutes. Transfer the eggs to cold water. When cool enough to handle, peel and slice them. Drain the potatoes, let them cool briefly, peel, and cut into slices about ¼ inch (6 mm) thick.
Gently poach the cod. Place the cod in a wide pan and cover it with fresh cold water. Bring the water just to a gentle simmer; do not let it boil hard, which can make the fish break apart. Cook for about 6 to 8 minutes, depending on thickness, until the fish is opaque and flakes easily. Check the thickest piece with a food thermometer: the USDA FSIS safe minimum for fish is 145°F (63°C). Lift out the cod and let it cool enough to handle. Remove skin and bones, then separate the flesh into large flakes. Check carefully for any remaining pin bones.
Soften the onions and garlic. Heat ⅓ cup (80 ml) of the olive oil in a wide skillet over medium-low heat. Add the sliced onions and bay leaves. Cook for 12 to 15 minutes, stirring occasionally, until the onions are soft, glossy, and sweet-smelling but not browned. Add the garlic and black pepper and cook for another 2 to 3 minutes. Taste a small piece of cod before adding any salt; salt cod can remain plenty salty even after soaking.
Layer the casserole. Heat the oven to 375°F (190°C). Lightly oil a shallow 2-quart (1.9 L) baking dish if it is not already well coated. Spread a thin layer of the onion mixture over the bottom. Add half the potatoes, then half the flaked cod and half the remaining onions. Repeat with the rest of the potatoes, cod, and onions. Spoon the onion-flavored oil evenly over the top, adding the remaining ⅓ cup (80 ml) olive oil only if the mixture looks dry. The layers can be rustic; avoid pressing them down, so the fish stays in generous flakes.
Bake and finish. Bake uncovered for 20 to 25 minutes, until the casserole is hot throughout and the edges are lightly sizzling. Arrange the sliced eggs and olives over the top during the final 5 minutes of baking, or add them after baking if you prefer the eggs to stay cool and distinct. Scatter with parsley. Let the dish stand for 5 minutes before serving so it is easier to portion.

Tips

Desalt to taste, not just by the clock. Salt cod thickness and curing vary. If you can, taste a tiny piece after soaking and poaching; it should be pleasantly seasoned, not harshly salty. Avoid adding salt to the onions or potatoes until the finished dish has been tasted.
Keep the water cold and the cod refrigerated. A roomy bowl lets water circulate around the pieces. If the cod is very thick, cut it into large portions before soaking so it desaltes more evenly, and keep changing the water on schedule.
Choose potatoes that hold their shape. Waxy or all-purpose potatoes make neat slices and are less likely to collapse in the casserole. If using russets, simmer them carefully and stop as soon as they are just tender.
Use a sensible substitute if needed. If dried salt cod is unavailable, use 1 lb (450 g) fresh or frozen cod, thawed if frozen, and season it lightly with salt. It will lack the concentrated, cured flavor of bacalhau, so season the onion mixture to taste; skip the long soak and cook the fresh fish only until it reaches 145°F (63°C).

Serving Suggestions

Serve Bacalhau à Gomes de Sá warm from its baking dish, with the egg slices, olives, and parsley distributed across each portion. A crisp green salad with a simple vinegar-and-olive-oil dressing balances the rich, soft potatoes, while steamed green beans or lightly dressed cabbage make an easy vegetable side. Crusty bread is useful for catching the olive oil and onion juices. Lemon wedges are optional: a little squeeze adds brightness, but the dish should still taste clearly of cod, onion, and olive oil.

For a relaxed meal, put the casserole in the middle of the table and let everyone serve themselves. Because potatoes and cod are filling, a modest portion alongside vegetables is usually enough. If serving guests, have the eggs and olives ready before the casserole comes out of the oven; arranging them at the last moment keeps the top looking fresh without delaying dinner.

Variations

This Porto-style preparation has variations from household to household. Some cooks poach the cod in milk instead of water, which gives the fish a milder, rounder flavor; the milk is discarded after poaching. Others add a little more olive oil or arrange the potatoes and fish in more distinct layers. These are useful adjustments rather than strict rules, and the central ingredients remain salt cod, potatoes, onions, olive oil, eggs, and olives.

For a more pronounced olive flavor, use a mix of black and green olives, or serve extra olives at the table. A small pinch of paprika can be added with the black pepper, though it is not essential to the traditional flavor. If you need to make a smaller batch, halve every ingredient and use a smaller baking dish; begin checking the casserole after about 15 minutes because a thinner layer may heat faster. Fresh cod is a practical substitute when salt cod cannot be found, but it makes a gentler, less savory dish and should not be soaked.

Storage and Reheating

Refrigerate leftovers within 2 hours of cooking, in a covered shallow container. They keep for 3 to 4 days in the refrigerator. For best quality, store the eggs separately if you know you will have leftovers; their texture can become firmer when reheated. Freezing is possible for up to about 2 months in a well-sealed container, although the potatoes may soften and become slightly grainy after thawing. Thaw overnight in the refrigerator.

Reheat a portion in a covered oven-safe dish at 325°F (165°C) until steaming hot, usually 20 to 30 minutes depending on portion size. Add a spoonful of water or olive oil if it looks dry. For a single serving, microwave in short intervals, stirring or turning the portion where possible. Reheated leftovers should reach 165°F (74°C) throughout, checked with a food thermometer; do not rely only on warm edges. Avoid repeatedly cooling and reheating the same portion.

Frequently Asked Questions

What does bacalhau mean? Bacalhau is the Portuguese word for cod, and in cooking it often refers to dried, salted cod. In Portugal, it is used in many different preparations, so the word does not name just one recipe. Bacalhau à Gomes de Sá is one well-known version, associated with the city of Porto.

Can I use salt cod without soaking it? No. Salt cod is preserved with a large amount of salt, so it needs a long cold-water soak before cooking. Cooking it directly from its salted state would make the dish overwhelmingly salty. Keep it refrigerated while soaking and change the water regularly; the exact time depends on how thick and salty the pieces are.

How can I tell when the cod has desalinated enough? After the planned soak, poach a small piece and taste it once it is cool enough. It should have a noticeable but not aggressive saltiness. If it is too salty, return the remaining cod to fresh cold water in the refrigerator for several more hours, then taste again. Do not try to correct badly oversalted fish by adding extra potatoes alone.

Can I prepare this dish ahead? Yes. You can desalt and poach the cod a day ahead, then refrigerate it promptly in a covered container. The potatoes can also be cooked and sliced ahead. Assemble the casserole shortly before baking for the best texture, or assemble it several hours in advance and refrigerate it; allow extra time in the oven so the center heats through. Keep raw soaking fish and cooked ingredients refrigerated.

Is milk required for this recipe? No. Some versions gently poach the soaked cod in milk, while others use water. Milk softens the flavor and adds a subtle richness, but it is not essential. If using it, heat it gently rather than boiling, poach the cod until cooked, and discard the milk afterward.

Can I make Bacalhau à Gomes de Sá with fresh cod? Yes, though the result is milder because fresh cod has not been cured and salted. Skip the desalting step, season the fresh fish lightly, and cook it to 145°F (63°C). Since the fish will not contribute as much salt or concentrated flavor, taste the onion mixture and finished casserole before serving and adjust cautiously.

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

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