从菜單上随意單點菜色

The basic idea is that what’s being ordered will be customized according to the client’s wishes (as opposed to set meals on a menu).

e.g. Sushi a la carte (单点某一款寿司)

Definition from Cambridge Adv. Learner's Dict:
a la carte adjective [before noun], adverb
If you eat a la carte, you choose each dish from a separate list instead of eating a fixed combination of dishes at a fixed price:
You get more choice if you eat a la carte/from the a la carte menu.
Compare table d'hote.

FYI:

http://en.wikipedia.org/wiki/À_la_carte
À la carte (also a la carte), is a French phrase meaning "from the menu", and it is used in restaurant terminology in one of two ways:
First, it may refer to a menu of items priced and ordered separately rather than selected from a list of preset multi-course meals at set prices.
Second, it may designate the option to order a main course item alone that is otherwise served with a side or starter dish, such as soup or salad.

英语点菜的两种表述：a la carte和tabled'hote_教育频道 - [ Translate this page ]
点菜有两种方式，一是a la carte（随意点菜），一是tabled' hote或fixed price meal（ 份饭，套餐），后一种有几道固定的菜肴和饮料，价格也是固定的。 ...
education.163.com/06/0216/09/2A2RFVQR00290165.html - 31k - Cached - Similar pages



a la carte - 维基词典，自由的多语词典 - [ Translate this page ]
a la carte ... 依菜單單點菜色. We ate a la carte. 来 自“http://zh.wiktionary.org/wiki/a_la_carte”. 分类: 英语 | 英语副词 ...
zh.wiktionary.org/wiki/a_la_carte - 10k - Cached – Similar pages