1 can (14-1/2 ounces) reduced-sodium chicken broth
1/2 pound fresh asparagus, trimmed and cut into 1-inch pieces
3 tablespoons sherry or additional reduced-sodium chicken broth
3 tablespoons cornstarch
1/2 cup fat-free milk
1-1/2 teaspoons minced fresh thyme
1/2 teaspoon salt
1/4 teaspoon pepper
10 sheets phyllo dough (14 inches x 9 inches)
Refrigerated butter-flavored spray
In a Dutch oven, bring water to a boil. Add pearl onions; boil for 3 minutes. Drain and rinse in cold water; peel and set aside.
In a large skillet, cook chicken in 1 tablespoon oil over medium heat until juices run clear; remove and keep warm. In the same pan, saute potatoes in remaining oil for 5 minutes. Add onions and mushrooms; saute 3 minutes longer. Add the broth, asparagus and sherry or additional broth. Bring to a boil. Reduce heat; cover and simmer for 5 minutes or until potatoes are tender.
Combine cornstarch and milk until smooth; stir into skillet. Bring to a boil; cook and stir for 2 minutes or until thickened. Drain chicken; add to onion mixture. Stir in the thyme, salt and pepper. Transfer to an 8-in. square baking dish coated with cooking spray.
Stack all 10 phyllo sheets. Roll up, starting at a long side; cut into 1/2-in. strips. Place in a large bowl and toss to separate strips. Spritz with butter-flavored spray. Arrange over chicken mixture; spritz again. Bake, uncovered, at 425° for 10-15 minutes or until golden brown.