In a large bowl, combine ground beef, grated onion, salt, marjoram, and pepper; mix well until evenly distributed.
Divide the meat mixture into 6 equal portions and shape into oval patties about 3/4-inch thick.
Preheat broiler and position oven rack 3 inches from heat source.
Broil Salisbury steak patties for 3 to 4 minutes on the first side.
Turn patties over and broil for about 4 minutes on the other side, or until cooked to desired doneness.
While patties are cooking, prepare gravy mix according to package directions.
Stir drained mushrooms and red wine into the prepared gravy and heat through.
Pour the mushroom wine gravy over the cooked Salisbury steak patties and serve immediately with potatoes.