Place turkey breast in a shallow baking pan; coat outside of turkey with nonstick cooking spray. Tuck onion and celery in breast cavity; place butter between meat and skin. Pour chicken broth and white wine into bottom of pan.
Combine lemon pepper, garlic powder, onion powder, sage, and paprika in a small bowl; rub seasoning mix over turkey.
Bake in preheated oven until a meat thermometer reads 175 degrees F (80 degrees C), basting every 30 minutes, 2-1/2 to 3 hours. Remove turkey and keep warm. Pour pan drippings into a cup and discard grease.
Combine flour and water in a saucepan until smooth. Pour in pan drippings and chicken bouillon. Bring to a boil over medium heat, stirring constantly, and cook until thickened, about 2 minutes. Slice turkey and serve with gravy.
