Stir together 1/2 cup flour, marjoram, 1/8 tsp salt, and 1/8 tsp pepper. Dredge fish in flour mixture. In a large skillet, cook fish in 2 Tbsp butter over medium high heat, 2-3 minutes per side. Remove fish from skillet and keep warm. In the same pan, cook mushrooms and green onion in remaining butter until tender. Add 2 Tbsp flour and cook for 1 minute. Add broth and marsala. Cook, uncovered, 2 to 3 minutes or until slightly thickened. Return fish to pan and heat through. Sprinkle with chopped fresh parsley, if desired.