Add mushrooms and white parts of green onions. Simmer, covered, 10 minutes, or until pork and vegetables are tender. Stir in green onion tops; cover and cook 3 minutes longer.
1/2 lb mushrooms, 1 bunch scallions
Meanwhile, blend cornstarch and 2 tablespoons water. Stir into meat mixture; cook, stirring, 1 minutes, or until sauce boils and thickens slightly.