Bacalhau à Zé do Pipo
(bah-kahl-YOW ah ZEH doo PEE-poo)
O Nosso Bacalhau
It sounds slightly insane—a salt cod casserole crowned with baked mayonnaise—but it is an absolute masterpiece of the Portuguese Sunday table. Invented in a mid-century Porto restaurant, this unpretentious dish relies on a strict old-world grandmother's edict: onions sweated soft in olive oil, but never allowed to brown. By poaching frozen, pre-desalted cod in milk and using that same oceanic liquid to hydrate the mashed potatoes and braise the onions, you build profound, nostalgic flavor from the ground up. It’s a magic trick of a recipe that brings genuine heritage cooking to a busy American weeknight.
Before you start
Thaw the cod.
Move the frozen cod from the freezer to the refrigerator the night before cooking to ensure it cooks evenly.
Ingredients
- frozen desalted salt cod loins1 1/2 lb
- whole milk3 cup
- dried bay leaves2 med
- Yukon Gold potatoes2 lb
- unsalted butter3 tbsp
- ground nutmeg1/4 tsp
- extra virgin olive oil4 tbsp
- yellow onions2 large
- cloves garlic2 med
- premium store-bought mayonnaise3/4 cup
- lemon juice1 tsp
- pitted black olives1/2 cup
- kosher salt1 tsp
- black pepper1/2 tsp
Method
- 01
Boil the potatoes.
Place the potatoes in a large pot of salted water, bring to a boil over medium-high heat, then simmer for about 15 minutes until perfectly fork-tender.
- 02
Poach the cod.
Place the thawed cod in a skillet, pour in the milk, drop in one bay leaf, and gently simmer over medium heat for 8 to 10 minutes until the fish flakes easily. Transfer the cod to a plate, but absolutely keep the milk in the pan—it is now infused with the flavor of the sea.
- 03
Mash the potatoes.
Drain the potatoes and mash them in their warm pot with the butter, nutmeg, salt, pepper, and a half cup of the reserved cod-infused milk until you have a smooth, sturdy purée.
- 04
Sweat the onions without browning.
This is the grandmother's trick: heat three tablespoons of olive oil in a skillet, add the sliced onions, garlic, and remaining bay leaf, then immediately splash in another half cup of the cod-infused milk. Simmer gently for 10 to 15 minutes until the onions melt and turn sweet without a single trace of color.
- 05
Assemble the casserole.
Preheat the oven to 400°F. Flake the cod into the center of a baking dish, smother it completely with the sweated onions, and spread a mixture of the mayonnaise, lemon juice, and remaining tablespoon of olive oil directly over the top. Border the entire dish with the mashed potatoes.
- 06
Bake and garnish.
Bake for 15 to 20 minutes until the mayonnaise puffs into a beautiful golden glaze and the potato peaks crisp up, then scatter the black olives over the top before serving.
Notes
Sourcing the cod.
Bypassing the traditional three-day soak is key to making this a weeknight reality. Look for commercially frozen, pre-desalted cod loins (Bacalhau Demolhado Ultracongelado) in the frozen seafood or ethnic aisles of well-stocked supermarkets.