Preheat oven to 350°F. Rinse the halibut with ice-cold water, and pat dry with paper towels. Cut into large chunks. Peel and cut the onion into large wedges. Peel the garlic and cut each clove in half. Zest and juice the oranges. Clean the parsley and thyme, remove the leaves, and keep leaves whole.

Heat the oil to high temperature in a Dutch oven or other heavy-bottomed ovenproof pan with a lid. Dust the fish with the flour. Sear until brown on both sides.

Add all the remaining ingredients except the capers and pepper. Bring to a quick boil, cover, and place the pan in the oven. Braise for 20 minutes or until the fish flakes.

Place the fish on a serving platter and drizzle with the pan juices. Sprinkle with the capers and pepper. Serve with cooked parsley and thyme from the pan for garnish.