Beer-battered halibut is all about the crisp, crunchy exterior, and this easy recipe shows you precisely how to get it. This 30-minute recipe delivers moist, never-greasy fish with a wonderful crust. Creamy tartar sauce brightened with tarragon and parsley is its ideal foil.
For the tartar sauce: In a bowl, add the parsley, tarragon, shallot, and cornichon. Chop the hard boiled egg by removing the yolk and crumbling it, then dice the white. Add both yolk and whites to the bowl. Add vinegar, salt, mustard, mayonnaise, and a few dashes of hot sauce (or more to taste). Stir to combine and set aside.
For the beer batter: In a large mixing bowl, mix the cake flour and baking soda with a fork. Slowly pour in the beer, stirring the entire time (it's okay if there are a few lumps). The batter should be thin, falling off the fork easily so it coats the fish, not heavy like pancake batter. Set aside.
Fry the halibut: Fill a deep heavy-bottomed pan with oil—don't go higher than 2 inches from the rim—and heat to 350 degrees F. Season the halibut with salt on both sides. Test the oil by cooking a few drops of batter; they should float to the surface when the oil's hot enough. Remove these "tester crunchies" with a slotted spoon. One piece at a time, drop the fish into the beer batter, then remove it, letting the excess drip off. Then place it halfway into the oil, letting a crust form for 10 seconds, then releasing it gently into the pan. Repeat with two more pieces (three at a time), so the pan isn't overcrowded and cook each for 3–4 minutes. Remove the fish to a baking sheet fitted with a wire rack to drain any excess oil. Season with flaky sea salt and serve with tartar sauce and lemon wedges.