After it's made, wrap and freeze this casserole for up to 1 month. To reheat, thaw overnight in the refrigerator, then cover with foil and bake at 350 degrees F according to recipe directions. You can also make this dish in individual ramekins and freeze for simple single servings; reduce the cooking time by 10 minutes. You can use store-bought rotisserie chicken instead of poaching the chicken breasts.