1-3/4 lb halibut steaks (or cod, or salmon)
2 tsp + 1/2 tsp extra-virgin olive oil
1/4 cup finely chopped flat-leaf parsley (start with a small bunch or handful)
1 clove garlic, minced
The zest of 1 small orange (grated on a fine grater or Microplane)
1/2 tsp capers, or more to taste, drained, roughly chopped
Coarse sea salt and fresh-ground black pepper, to taste
Preheat oven to 400°F. Place fish in a nonstick roasting pan. Rub on all sides with 2 tsp olive oil, and season with sea salt and black pepper. Roast for 10-15 minutes, depending on the thickness of the fish.
While the fish is cooking, place all remaining ingredients in a bowl and mix to yield a rough paste, or blend in a food processor. (Can be stored in the refrigerator for 1-2 days in a container with an air-tight lid.)
Serve the fish hot from the oven, topped with gremolata.