Meanwhile, in a large skillet, heat olive oil and butter. Dip filets in the flour mixture and shake off excess flour. Then dip filets in the beaten egg.
Quickley add filets to the skillet and cook for 3-4 minutes per side, until lightly browned. Remove filets to a dish.
In same skillet add broth and white wine (if using). You can add all broth if not using wine. Add lemon juice at this time. Scrape pan, and sprinkle a little seasoned flour into broth to thicken it. Add filets back to pan and simmer on low for 5 minutes. Serve with your choice of rice or potato, and a vegetable.