** Chicken breasts can be substituted for thighs,

Remove chicken meat from bones in large pieces. Shred meat into 1- inch long pieces. You should have 2 cups.

In a large kettle or saucepot, start cooking pasta in boiling water following package directions for al dente stage.

While pasta is cooking, whisk together egg whites with 3 tablespoons of the cornstarch and the garlic in medium bowl. Add the chicken shreds; toss to coat. Let stand for 5 minutes.

In another bowl, smooth the remaining 2 tablespoons cornstarch with part of the water. Stir in remaining water, vinegar, soy sauce, and red pepper flakes; set aside.

Coat a large wok or heavy skillet with the oil. Heat over medium- high heat until the oil begins to sizzle. Lift chicken pieces from egg white mixture, letting excess drip back into bowl. Stir-fry until golden brown, about 5 minutes. Lift out with slotted spoon to paper towels. Wipe out wok or skillet.

Place wok over medium heat. Whisk the reserved cornstarch/soy mixture again and pour into wok. Bring mixture just to a boil. Add mushrooms and onions. Cook, stirring constantly, until sauce thickens, about 3 minutes. Add the cooked chicken pieces and heat, stirring constantly, until chicken and vegetables are glistening and mixture is hot.

Drain pasta and place on a large serving platter. Top with the chicken/vegetable mixture.