In a medium mixing bowl stir together egg white, soft bread crumbs, º cup of the onion, milk, salt, thyme, and pepper. Add turkey; mix well. Shape mixture into 1-inch meatballs.
Spray a 13x9x2-inch baking pan or baking dish with nonstick spray coating. Place meatballs in the baking pan or dish. Bake, uncovered, in a 350∞ oven for 30 to 35 minutes or till meatballs are no longer pink. Drain any juices; cool meatballs. Then, cover and chill meatballs for 2 to 24 hours.
Before serving, spray a cold large skillet with nonstick spray coating. Add mushrooms and remaining º cup onion. Cook till mushrooms and onions are tender. Stir together water, cornstarch, and bouillon granules. Carefully add cornstarch mixture to mushroom mixture in skillet. Cook and stir till thickened and bubbly. Add chilled meatballs and wine; heat through. Stir in parsley. Serve over hot cooked noodles.
