Heat oven to 400 degrees. ... or 3 quart casserole. Cook onion in butter ... onions and fillets. Bake uncovered 25 to 30 minutes ... and fillets are hot.
Preheat oven to 350 degrees. Spray shallow 2-quart flameproof casserole with nonstick cooking spray. Arrange ... salt and pepper; bake until fish flakes easily when tested with ... Serve garnished with parsley.