Spread softened butter over each side of the French bread. Top with garlic, parsley, black pepper and salt.
Bake until butter has melted (about 5-10 minutes). Keep warm in oven.
Meanwhile, melt 2 tbsp butter in a large skillet over medium-high heat. Add the onion and peppers, season with garlic powder, parsley, oregano, black pepper and salt; sautee until softened (about 5-10 minutes).
Layer sliced flank steak over one side of the French bread, top with onion and peppers mixture and cover with cheese.
Return the sandwich to the oven until the cheese has melted (about 3-5 minutes).