Pickled onions are a popular pickled food consisting of onion

Onion

The onion , also known as the bulb onion, common onion and garden onion, is the most widely cultivated species of the genus Allium. The genus Allium also contains a number of other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion The onion...

s pickled

Pickling

Pickling, also known as brining or corning is the process of preserving food by anaerobic fermentation in brine to produce lactic acid, or marinating and storing it in an acid solution, usually vinegar . The resulting food is called a pickle. This procedure gives the food a salty or sour taste...

 in a solution of vinegar

Vinegar

Vinegar is a liquid substance consisting mainly of acetic acid and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. Commercial vinegar is produced either by fast or slow fermentation processes. Slow methods generally are used with traditional...

 and salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

, often with other preservatives and flavourings. In the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 they are often eaten alongside fish and chips

Fish and chips

Fish and chips is a popular take-away food in the United Kingdom, Australia, New Zealand and Canada...

 or as part of a ploughman's lunch

Ploughman's lunch

A ploughman's lunch is a cold snack or meal originating in the United Kingdom, served in pubs, sometimes eaten in a sandwich form, composed of cheese ; often cooked ham slices, pickle , apples, pickled onions, salad leaves, bread...

. There is a variety of small white pickled onions known as 'silverskin' onions, most frequently used as an essential component of the Martini cocktail variant known as a Gibson

Gibson (cocktail)

The Gibson is a cocktail made with gin and vermouth, and garnished with a pickled onion. The drink bears great similarity to another cocktail, the martini, with the onion garnish being the only differentiating factor.-History:The exact origin of the Gibson is unclear, with numerous popular tales...

.

In the United Kingdom, pickled onions are also often sliced and added to sandwiches, especially cheese sandwich

Cheese sandwich

A cheese sandwich is a basic sandwich made generally with one or more slices of any kind of cheese on any sort of bread. In addition to the cheese, it may also include pepperoni, lettuce, bacon, tomatoes, pickles and/or condiments such as mustard or mayonnaise...

es.

Pickled onions are pickled in malt vinegar and the onions are about an inch in diameter. Silverskin onions are pickled in white vinegar, and are much smaller.

In the Southern United States

Cuisine of the Southern United States

The cuisine of the Southern United States is defined as the historical regional culinary form of states generally south of the Mason Dixon Line dividing Pennsylvania from Maryland and Delaware as well as along the Ohio River, and extending west to Southern Missouri, Oklahoma and Texas.The most...

, pickled Vidalia onion

Vidalia onion

A Vidalia onion is a sweet onion of certain varieties, grown in a production area defined by law in Georgia and by the United States Code of Federal Regulations . The varieties include the hybrid yellow granex, varieties of granex parentage, or other similar varieties recommended by the Vidalia...

s can be served as a side dish.

In Hong Kong

Hong Kong

Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...

, pickled onions are served in a lot of Cantonese restaurant

Cantonese restaurant

A Cantonese restaurant is a type of Chinese restaurant that originated from Southern China. This style of restaurant soon flourished in Hong Kong.-History:Some of the earliest restaurants in Colonial Hong Kong were influenced by Cantonese people...

s, especially around dinner time, as a small dish before the main course is served.

In Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

, they are served to accompany raclette

Raclette

Raclette is both a type of cheese and a Swiss and French dish based on heating the cheese and scraping off the melted part.-Cheese:Raclette is a semi-firm, cow's milk cheese - most commonly used for melting...

, along with pickled gherkins(a small type of cucumber).