A simple, quick sauce is made here by swirling butter, lemon juice, and herbs into the braising liquid. Variations on this dependable theme are endless; for inspiration, see Beurre Blanc and About Flavored Butters.
Preheat the oven to 350°F. Place in a baking dish just large enough to hold the fish:
Sprinkle the fish with:
Pour into the dish:
Cover tightly with a lid or foil and bake for 15 to 25 minutes, depending on the thickness of the fish. The flesh should be firm and opaque throughout, or reach an internal temperature of 125° to 130°F, the latter temperature for flakier fish (for more on how to test for doneness, see here). Place the fish on a platter and cover to keep warm. Swirl into the liquid in the baking dish until melted:
Stir in:
Pour the sauce over the fish.