Slice onions and pepper and place in a large baking pan. Drizzle with olive oil.
Mix orange juice, mustard, parsley, sesame oil, salt and pepper. 3. Place sea bass over onions and pour the sauce over it.4. Bake at 400F for 20 minutes, reduce the heat to 350F and bake 10 minutes more.
The cooked fish should be flaky and tender. So be careful not to overcook it. Do not be afraid, you will master this in one time.