Preparation Pat fish dry and season with 1/2 teaspoon each of salt and pepper, then dredge in flour, shaking off excess. Heat 3 tablespoons oil in a 12-inch heavy skillet over high heat until it shimmers. Cook fish, skin side down first, turning once, until cooked through, crisp, and golden on both sides, 3 to 4 minutes total. Transfer fish to a large baking dish (not aluminum) and wipe out skillet. Add remaining 1/2 cup oil to skillet and cook onion over medium heat, stirring occasionally, until softened, 3 to 4 minutes. Add mushrooms, coriander, red pepper flakes, zest, and 1/2 teaspoon salt and cook, stirring occasionally, until mushrooms are golden, about 5 minutes. Stir in vermouth. Remove from heat and stir in vinegar and lemon juice, then pour over fish. Cool to room temperature, about 30 minutes. Transfer fish to plates. Stir mint into mushroom mixture and spoon over fish. Serve at room temperature. Cooks' note:Escabeche can marinate, chilled, 1 day.
Preparation Pat fish dry and season with 1/2 teaspoon each of salt and pepper, then dredge in flour, shaking off excess. Heat 3 tablespoons oil in a 12-inch heavy skillet over high heat until it shimmers. Cook fish, skin side down first, turning once, until cooked through, crisp, and golden on both sides, 3 to 4 minutes total. Transfer fish to a large baking dish (not aluminum) and wipe out skillet. Add remaining 1/2 cup oil to skillet and cook onion over medium heat, stirring occasionally, until softened, 3 to 4 minutes. Add mushrooms, coriander, red pepper flakes, zest, and 1/2 teaspoon salt and cook, stirring occasionally, until mushrooms are golden, about 5 minutes. Stir in vermouth. Remove from heat and stir in vinegar and lemon juice, then pour over fish. Cool to room temperature, about 30 minutes. Transfer fish to plates. Stir mint into mushroom mixture and spoon over fish. Serve at room temperature. Cooks' note:Escabeche can marinate, chilled, 1 day.