Halibut à la Nage with Parsnips and Tarragon
SERVES 4
TIME 1¼ hours
Ingredients:
TARRAGON OIL
Kosher salt (for blanching herbs)
⅓ cup fresh parsley leaves
1 tablespoon fresh tarragon leaves
⅓ cup vegetable oil
FISH
4 (5- to 6-ounce) skinless halibut fillets, ¾ to 1 inch thick
2 teaspoons kosher salt, divided
2 cups water
6 ounces parsnips, peeled and sliced thin
1 shallot, sliced thin
1 piece Parmesan cheese rind, about 2½ inches by 1 inch
2 (3-inch) strips lemon zest plus 2 teaspoons lemon juice, plus extra juice for seasoning
½ teaspoon black peppercorns
¼ teaspoon vanilla extract
3 sprigs fresh tarragon, plus extra for garnish
1 tablespoon whole grain mustard
Before You Begin: To ensure the proper volume, pack the parsley tightly in the measuring cup. Process the oil in a blender; an immersion blender will not process the herbs as finely, producing a paler colored oil. You can substitute other flaky white fish such as cod, haddock, pollock, or hake for the halibut; choose uniformly thick fillets to ensure even cooking.
1. FOR THE TARRAGON OIL: Bring 6 cups water and 2 teaspoons salt to boil in large saucepan. Add parsley and cook until leaves are tender but still bright green, about 30 seconds. Stir in tarragon, then drain herbs in fine-mesh strainer. Run under cold water until herbs are cool, about 10 seconds. Squeeze dry and transfer to blender. (Reserve strainer.) Add oil and process until herbs are finely ground and oil is bright green, about 2 minutes. (Oil can be refrigerated for up to 24 hours.)
2. FOR THE FISH: Sprinkle halibut all over with 1 teaspoon salt and set aside. Add water, parsnips, shallot, cheese rind, lemon zest, 2 teaspoons lemon juice, peppercorns, vanilla, and remaining 1 teaspoon salt to 12-inch skillet and bring to boil over high heat. Adjust heat to maintain gentle simmer, cover, and cook for 25 minutes.
3. Return liquid to boil over medium-high heat. Nestle halibut skinned side down in liquid, moving aside solids as much as possible (liquid will not quite cover fillets). Add tarragon and spoon some liquid over halibut. Reduce heat to low; cover and simmer gently until fish registers 110 degrees at thickest point, 4 to 7 minutes. Let stand off heat, covered, until fish is opaque and just cooked through (fish should register at least 135 degrees), 3 to 7 minutes.
4. Divide halibut among four shallow bowls. Season broth with salt and lemon juice to taste. Strain broth into 4-cup liquid measuring cup (you should have about 1⅔ cups broth) and discard solids. Divide broth evenly among bowls. Garnish with tarragon leaves. Top each piece halibut with ¾ teaspoon mustard. At table, drizzle about 1 tablespoon tarragon oil into each bowl. Serve immediately.
Why This Works: Our easy, elegant poached halibut is inspired by the classic French preparation called “la nage” in which fish is delicately cooked and served in well-seasoned, lightly acidulated broth. For a non-traditional Western European riff, we made a broth infused with parsnip, Parmesan, lemon, vanilla, and tarragon. Gently poaching the fish until it reached 110 degrees, then letting it sit, covered, off heat, ensured that it came up to temperature (135 degrees) gradually and didn't overshoot the mark. Garnishing the plated fish and broth with a rich, verdant herb oil and additional fresh herbs added pops of flavor and color, not to mention professional-looking polish.
Recipes provided by America’s Test Kitchen; used with permission.
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