This slow-roasted cod topped with zesty relish is just the thing for an end-of-winter dinner party.
Ingredients
2 lemons
1/2 small red onion, very thinly sliced into rings
1 teaspoon kosher salt plus more
1/2 cup Castelvetrano or other brined green olives (about 24), coarsely chopped
2 tablespoons drained capers, chopped
1 1/4 cups olive oil, divided
Kosher salt, freshly ground pepper
8 6-ounce pieces skinless cod fillets
2 dried red chiles, stemmed, or 1/4 teaspoons crushed red pepper flakes
1/4 cup fresh flat-leaf parsley leaves
Directions
Finely grate zest from lemons; set aside. Using a sharp knife, cut peel and white pith from lemons; discard. Working over a medium bowl, cut between membranes to release segments into bowl and squeeze membranes to release juices; discard membranes and any seeds. Set lemon segments aside.
Combine onion and 1 teaspoon salt in a small bowl. Let sit 10 minutes. Squeeze onion to remove any excess liquid; add to bowl with lemon segments. Add olives, capers, reserved lemon zest, and 3/4 cup oil; season with salt and pepper and toss to combine. Cover relish and chill at least 4 hours.
Preheat oven to 250°F. Bring relish to room temperature.
Place cod in a large shallow baking dish or roasting pan and drizzle with remaining 1/2 cup oil. Add chiles and turn fish to coat; season with salt. Roast until just cooked through, 30–40 minutes.
Transfer fish to a platter. Mix parsley into relish and spoon over fish.
DO AHEAD: Relish (without parsley) can be made 1 day ahead. Keep chilled.
