Wipe filets with a damp cloth and heat oil in an oven-proof dish. Add onion, parsley, garlic, tomatoes, salt and pepper to taste. Place filets over top of vegetables. Cover and bring to boil. Lower flame. Simmer for 15 minutes. Add wine and bring to boil. Transfer dish to 350-degree oven. Bake 10 minutes or until fish flakes easily with fork. Carefully remove fish from sauce using a large spatula and keep the filets warm on a heated platter. Strain sauce through fine sieve and heat to boiling. Sauce should be reduced by this time. Pour the hot sauce over filets.