PREHEAT oven to 350° F. Lightly grease 13 x 9-inch baking dish.
PREPARE pasta according to package directions, adding frozen vegetables to boiling pasta water for last minute of cooking time; drain. Return pasta and vegetables to cooking pot.
MEANWHILE, HEAT oil in medium saucepan over medium heat. Stir in flour, garlic powder, salt and pepper; cook, stirring constantly, for 1 minute. Remove from heat; gradually stir in broth. Return to heat; bring to boil over medium heat, stirring constantly. Stir in evaporated milk and 1/2 cup cheese; cook over low heat until cheese melts. Remove from heat. Stir in turkey.
POUR cheese sauce over pasta and vegetables; mix lightly. Pour into prepared baking dish. Sprinkle with remaining 1/4 cup cheese.
BAKE for 20 to 25 minutes or until lightly browned. Serve immediately.