2 (5 to 6-ounce) fillets of sea bass or other firm-fleshed white fish, with skin
4 teaspoons olive oil
2 teaspoons fresh lemon juice
1/4 teaspoon fennel seeds, chopped fine
Preheat oven to 425*F (220*C).
Rinse fillets and pat dry. Season fillets with salt and pepper. In a 9- to 10-inch cast-iron skillet (or non-stick skillet with handle wrapped in foil) heat 1 teaspoon oil over moderately high heat until hot but not smoking and sear fillets skin side down, pressing flat with a metal spatula to prevent curling, 2 minutes. Transfer skillet to middle of oven and roast fillets 5 minutes, or until just cooked through.
While fish is roasting, in a small skillet whisk together remaining 3 teaspoons oil, lemon juice, fennel seeds, and salt and pepper to taste and heat over moderately low heat until hot but not smoking.
Serve fillets skin sides up and spoon sauce over them.