Preheat oven to 400F. On 10 x 15 x 2-inch jellyroll pan, arrange bread cubes. Bake 5 to 10 minutes or until cubes are dry. Reserve 1/2 cup of bread cubes for topping.
Coat a 8 or 9-inch square baking dish with nonstick cooking spray. Layer bread cubes in bottom of dish.
In medium-size bowl combine smoked turkey, mushrooms, pimiento )if using), onion, chives, garlic powder, salt and pepper. Spread turkey mixture over bread cube layer and top with cheese. Sprinkle reserved bread cubes over cheese.
In same bowl combine milk and eggs; pour over top of bread layer. Cover dish and refrigerate overnight.
Take baking dish out of refrigerator and let sit at room temperature fo 30 minutes. Preheat oven temperature to 325F.
Bake strata 50 to 60 minutes or until knife inserted in center of strata comes out clean. Allow strata to stand 10 to 15 minutes before serving.