One Shot

It sounds like you are referring to a type of food called a "shooter" or "shot" that is served in restaurants in the USA. A shooter or shot is a small glass or cup that typically contains a single serving of a mixed drink or flavored liquid, often intended to be consumed quickly in one gulp.

Shooters or shots can be made with a variety of ingredients, such as liquor, juice, cream, or syrup. They are sometimes served as a way to sample a variety of flavors or as a fun way to enjoy a mixed drink.

Some examples of popular shooters or shots include:

I hope this helps! Let me know if you have any other questions.