Leek soup is a soup based on potatoes, leeks, broth

Broth

Broth is a liquid food preparation, typically consisting of either water or an already flavored stock, in which bones, meat, fish, cereal grains, or vegetables have been simmered. Broth is used as a basis for other edible liquids such as soup, gravy, or sauce. It can be eaten alone or with garnish...

 (usually
chicken), and heavy cream. Other things used may be 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...

 and
pepper

Black pepper

Black pepper is a flowering vine in the family Piperaceae, cultivated for its fruit, which is usually dried and used as a spice and seasoning. The fruit, known as a peppercorn when dried, is approximately in diameter, dark red when fully mature, and, like all drupes, contains a single seed...

, and various spices.

Generally the potatoes are diced and cooked in broth, while the leeks
are chopped and sauteed. After this all ingredients are combined and
stirred. Chives may be used for garnish

Garnish

A garnish is an item or substance used as a decoration or embellishment and often a flavor component on a prepared food dish or drink. In many cases, it may give added or contrasting flavor, some garnishes are selected first to augment the visual impact of the plate, while others are selected...

.

Leek soup is strongly associated with Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

, and is an important
item of Welsh cuisine

Welsh cuisine

Welsh cuisine is the cuisine of Wales. It has influenced, and been influenced by, other British cuisine. Beef and dairy cattle are raised widely. Sheep farming is extensive in the country and lamb is the meat traditionally associated with Welsh cooking, particularly in dishes such as roast lamb...

.