Season halibut with salt and pepper. Measure thickness of halibut at the thickest part. Place 1/2 of onion and lemon in roasting pan. Add halibut. Place remaining onion and lemon over; pour wine over all. Cover with boil and bake at 450 degrees, allowing 10 minutes cooking time per inch of halibut or until halibut flakes easily with a fork. Serve with onion parsley sauce.
Onion Parsley Sauce:
Cook 1 cup sliced onion in 3 tablespoons butter over low heat about 15 minutes or until tender. Add 4 teaspoons flour, 1/4 teaspoon salt and a dash of pepper. Cook until smooth and bubbly. Gradually add 1 1/4 cup milk; heat to boiling, cook and stir 1 minute. Stir in 1/4 cup minced parsley, 1 1/2 teaspoons lemon juice and a dash of bottled hot pepper sauce. Makes about 1 1/2 cups.
