1Heat oven to 450°F. Spray 15x10x1-inch pan with cooking spray. Place burgers on one side of pan. Place bell pepper, onion and mushrooms on other side of pan. Spray vegetables with cooking spray for about 3 seconds; sprinkle with seasoned salt.
2Bake 10 minutes. Remove mushrooms from pan. Turn burgers and vegetables; bake 5 to 8 minutes longer or until vegetables are tender and burgers are hot.
3In small bowl, mix topping ingredients. Spread topping on insides of pita bread halves. Fill each pita bread half with lettuce, burger and vegetables.