In a 12-inch skillet cook mushrooms and green onions in 2 teaspoons of the butter for 4 to 5 minutes or until tender. Remove from skillet, reserving drippings. Set aside.
Meanwhile, cut veal into 2 serving-size pieces. Place each piece of veal or chicken between 2 sheets of plastic wrap. Working from center to edges, pound lightly with the flat side of a meat mallet to about 1/8-inch thickness. Remove the plastic wrap.
Sprinkle veal with salt and pepper. In the same skillet cook veal in the remaining 2 teaspoons butter over medium-high heat about 2 minutes or until cooked through, turning once. Transfer to dinner plates. Keep warm.
Add Marsala and broth to drippings in skillet. Bring to boiling. Boil gently, uncovered, about 1 minute, scraping up any browned bits. Return mushroom mixture to skillet; add parsley. Heat through. To serve, spoon the mushroom mixture over meat. Makes 2 servings.