One 6-ounce mahi-mahi fillet (may substitute swordfish)
Kosher or sea salt
Pinch celery seed (optional)
4 ribs celery, with leaves
1 tablespoon extra-virgin olive oil
1 medium clove garlic, crushed
2 large shallot lobes, cut into thin slices (about ⅓ cup)
¼ teaspoon crushed red pepper flakes
2 tablespoons pitted black olives, cut into quarters
1 tablespoon tomato paste
½ cup hot water, or more as needed
½ teaspoon Thai fish sauce
Sprinkle the mahi-mahi with salt and celery seed, if using.
Trim the celery by shaving off the thick skin and strings with a vegetable peeler. Cut the ribs crosswise, including leafy parts, into 4-inch pieces.
Heat the oil in a medium saucepan over medium heat. Once the oil shimmers, stir in the garlic and shallot; cook until they start to soften, about 2 minutes. Add the celery, sprinkle it with the crushed red pepper flakes and toss, making sure the celery is evenly coated with the oil. Stir in the olives; increase the heat to medium-high, and cook until the celery and shallots have browned lightly, about 5 minutes.
Combine the tomato paste and water in a liquid measuring cup; once the paste has dissolved, pour the mixture into the pan along with the fish sauce. Bring to a boil, then cover the pan and reduce the heat to medium or medium-low so the liquid is bubbling gently. Cook, stirring occasionally, until the celery has softened, about 20 minutes. Add a few more tablespoons of hot water if the mixture seems dry. Set the fish on top of the mixture; cover the pan and steam the fish until it has just cooked through and the celery is very tender, about 10 minutes.
If the fish is done before the celery, transfer the fillet to a plate and cover it loosely with aluminum foil. Finish cooking the celery as needed.
Spoon the celery mixture over the fish and eat the dish hot or at room temperature.
@Recipe nutrition:Nutrition values per serving: 400 calories, 19 g fat (2 g saturated), 19 g carbohydrates, 4 g fiber, 43 g protein, 160 mg cholesterol, 930 mg sodium.
Adapted from "Lidia Cooks From the Heart of Italy" by Lidia Bastianich (2009 Knopf)