Cod with Lemon, Green Olive, and Onion Relish

Ingredients

• 2 tablespoons capers drained chopped
• 48 ounce filets skinless
• 0.3 cup flat-leaf parsley leaves fresh
• 8 servings kosher salt freshly ground
• 2  lemons 
• 1.3 cups olive oil divided
• 2  chiles dried red stemmed crushed
• 0.5 small onion red very thinly sliced into rings
• 0.5 cup castelvetrano green coarsely chopped ( 24)

Equipment

• bowl
• oven
• knife
• baking pan
• roasting pan

Directions

1. 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.
2. Combine onion and 1 teaspoon salt in a small bowl.
3. Let sit 10 minutes. Squeeze onion to remove any excess liquid; add to bowl with lemon segments.
4. 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.
5. Preheat oven to 250°F. Bring relish to room temperature.
6. Place cod in a large shallow baking dish or roasting pan and drizzle with remaining 1/2 cup oil.
7. Add chiles and turn fish to coat; season with salt. Roast until just cooked through, 30–40 minutes.
8. Transfer fish to a platter.
9. Mix parsley into relish and spoon over fish.
10. DO AHEAD: Relish (without parsley) can be made 1 day ahead. Keep chilled.