Cut veal into four serving-size pieces. Place each veal piece between two pieces of plastic wrap. Use the flat side of a meat mallet to lightly pound each slice to about 1/8-inch-thick, working from center to edges. Remove plastic wrap. Set meat aside.
In a 12-inch skillet cook the mushrooms in 2 teaspoons of the hot oil for 4 to 5 minutes or until tender. Remove from skillet; set aside.
Sprinkle meat with the 1/4 teaspoon salt and the pepper. In the same skillet cook veal, half at at time, in the remaining 2 teaspoons hot oil over medium-high heat for 2 to 3 minutes or until no longer pink, turning once. Transfer to dinner plates; keep warm.
Add Marsala to drippings in skillet. Bring to boiling. Boil mixture gently, uncovered, for 1 minute, scraping up any browned bits. Return mushrooms to skillet; add green onions and sage. In a small bowl stir together cold water, cornstarch, and the 1/8 teaspoon salt; add to skillet. Cook and stir until slightly thickened and bubbly; cook and stir 1 minute more. To serve, spoon the mushroom mixture over meat. Serve immediately. If desired, serve with noodles and garnish with herb sprigs.