leaves. Herbs and spices Coriander and green onion leaves can be found in most Vietnamese dishes. A basic technique of stir-frying vegetable is frying garlic or shallot with oil before putting the vegetable into the pan. In northern Vietnam, dishes with fish may be garnished with dill. In central Vietnam, the mixture of ground lemongrass and chili pepper is frequently used in dishes with beef. In southern Vietnam, coconut water is used in most stew dishes. The pair culantro (ngò gai) and rice paddy herb (ngò om or ngổ) is indispensable in all kinds of sour soups in the southern Vietnam. Spearmint is often used with strongly fishy dishes. Perilla is usually used with crab dishes. Pairing Chicken dishes are combined with lime leaves. Crab and seashell dishes are combined with fishy-smelling herb and perilla. Dishes reputed as "cold" or "fishy-smelling", such as catfish, clams, or snails, are combined with ginger or lemongrass. Beef dishes are combined with celeries or pineapples. Sauces Nước chấm Mắm tôm (shrimp paste) Nước mắm (fish extract) can be used as it is or mixed with lemon juice, garlic, vinegar, sugar, and chili. This mixture is called nước mắm pha. Tương is made from fermented soybeans. Soy sauce mostly is used in marinades and sauces. Hoisin sauce is used in Southern Vietnam to mix with phở while serving. Hot chili sauce. Food colourings Traditionally, the colouring of Vietnamese food comes from natural ingredients, however today there's an increase in the use of artificial food dye agents for food colouring, in Vietnam. Red – usually from beetroot or by frying annatto seeds to make oil (dầu điều) Orange – usually used for sticky rice, comes from gac Yellow – from turmeric Green – from the pandan leaf or katuk Purple – from the magenta plant (lá cẩm) Black – in banh gai is from the ramie leaf (lá gai) Dark brown – for stew dishes, uses nước màu or nước hàng, which is made by heating sugar to a temperature above that of caramel (170 °C). Colourings can be absorbed by mixing ground colourings or colouring liquid or wrapping before boiling to get the extracts. When colouring dishes, the tastes and smells of colourings must also be considered. Popular dishes When Vietnamese dishes are referred to in English, it is generally by the Vietnamese name without the diacritics. Some dishes have gained descriptive English names, as