1. In a large bowl, mix together 1/3 cup condensed French onion soup with ground beef, bread crumbs, egg, salt and black pepper. Shape into 6 oval patties.
2. In a large skillet over medium-high heat, brown both sides of patties. Pour off excess fat.
3. In a small bowl, blend flour and remaining soup until smooth. Mix in ketchup, water, Worcestershire sauce and mustard powder. Pour over meat in skillet. Cover, and cook for 20 minutes, stirring occasionally.
My Note: Here are the changes I made to what is now my favorite dish. In the gravy, I used a can of French Onion soup as well as a can of Cream of Mushroom and a packet of Dry Onion Soup or sauteed onions. I omitted the salt due to the high sodium content in the soups. I'm glad I did. I doubled the gravy except for the ketchup -- kept it at 1/4 cup while doubling the rest. I also added a jar of mushrooms to the gravy. After browning each side of the patties (and yes, having them fall apart slightly), I transferred the patties to a foil-lined casserole dish, put the gravy on top, covered the dish, and cooked it at 375*F. for 45 minutes. I was worried the patties wouldn't get all the way done because they were pretty thick, but they turned out perfect! so simple to make. So, if you're craving an old cafeteria food favorite - don't waste your time with the recipe for the sauce - buy a box of Lipton Mushroom Onion soup mix and make the gravy with it - you won't regret it! We had it with brown rice (and had just enough wonderful gravy to go along with it!) and steamed broccoli. This is a new favorite recipe for my wife and me. For those who had trouble keeping the patties together, try this it was suggested to me. Instead of cooking in a skillet, place browned patties in a foil-lined casserole dish, pour gravy over top, and bake at 400 for 30 minutes Your patties will stay together nicely! I do like to play with my food. I would love to hear any improvements and/or variations you make to this simple recipe. Enjoy!