这家餐厅的隐藏菜品是他们的特色，你可以问问服务员有没有off-the-menu的选择。

The restaurant's secret specialties are their highlights, you can ask the waiter if there are any ___off-the-menu options.

他们提供了一些不在菜单上的特殊服务，只有熟客才知道。

They offer some ___off-the-menu services that only regular customers know about.