Combine ground chuck, 1/4 cup parsley, scallions, salt and pepper. Divide evenly into four portions. Shape each into 3/4 to 1 inch thick oval patties. Place 2 tbs flour in a shallow dish. Dredge each patty in flour, reserve 1 tsp flour. Heat oil in a saute pan over medium-high heat Add patties and saute 3 minutes on each side or until browned. Remove from pan.
Add onions and sugar to pan saute 5 minutes Stir in garlic and tomato paste; saute until paste begins to brown, 1 minute. Sprinkle mixture with reserved flour, cook 1 minute. Stir in broth, wine salt and thyme. Return meat to pan and bring sauce to a boil. Reduce heat to medium low and cover and simmer 10 minutes. Serve steaks on cheese toasts with onion sauce ladled over. Garnish with parsley and parmesan