Paracress

I've yet to use paracress as it is mostly confined to Latin America and used fresh, so unlikely to appear in European cooking.

Paracress plants	Paracress flower	Paracress leaves

Species:	Spilanthes acmella, s. oleracea.
Origin:	South America.
Source:	Both types of paracress are native to tropical Brazil.
Used Part:	Leaves and flowers (more correctly, flower heads). In both cases the herb is best used fresh.
Family:	Asteraceae (daisy family).
Effect:	Paracress has no particular odour, but when eaten it has an interesting flavour that develops slowly from salty and pleasant to strong, tickling and burning with some numbness in the mouth. Paracress is reminiscent of several other spices, notably Sichuan pepper but also water pepper and Tasmanian pepper. It is, however, different from the true cresses and better known pungent spices such as pepper or chilli.
Etymology:	Paracress is named after the Brazilian province Pará, this origin being reflected in the common names in various languages (e.g. Dutch Braziliaanse cresson, English "Brazil cress", French cresson de Para and Portuguese Agrião do Brasil).
	The meaning of genus name spilanthes is "blooming spot", from Greek spilos "spot" and -anthēs "blooming" or "flowered" (from anthos "flower"), presumably due to the striking shape and colour of the flower.
	The species name oleracea implies an edible herb, from Latin elements oler-, "potherb" and –aceus, implying a family of plants. Species name acmella is a Latinised diminutive of the Greek akmē meaning "highest point" or "peak", related to Latin acer "acute" or "sharp".
	Names such as Swedish tandvärksplanta and synonymous English "toothache plant" refer to the anaesthetic action of the alkamid constituents of paracress.
Uses:	Paracress has nothing in common with real cresses except the name, having culinary properties quite different from those of garden cress or water cress. Volatile isothiocyanates of cresses produce a quickly developing pungency in the mouth and nose that fades quickly, whereas the pungency of paracress develops slowly and is confined to the mouth where tickling may lead over time to a numb feeling. The flavour of paracress is more resistant to boiling than the flavour of true cress, but after prolonged cooking the leaves become mild and can be eaten as a vegetable.
	Culinary use of paracress is almost restricted to tropical Brazil, particularly the provinces of Acre, Amazonas, Pará and Ceará where the herb is much used in the cuisines of the indigenous peoples and is often used to add flavour (and vitamins) to the bland tasting manioc tubers eaten as a carbohydrate staple. Duck fried and then stewed in manioc juice flavoured with garlic (tucupí) is a popular food in all Amazonian provinces (pato no tucupí). Another recipe from the region is tacacá, a soup thickened with manioc juice that contains dried shrimps and sometimes freshwater fish. Both dishes are flavoured with garlic and paracress leaves, sometimes also with hot chillies. Simultaneous use of two pungent spices (chilli and paracress) gives a unique taste that cannot easily be described but is somewhat comparable to the use of Sichuan pepper in hot Chinese Sichuan cooking.
	Outside of Brazil, paracress is little known and little used as a food. A related species grown in South-East Asia has leaves that are boiled and used as a vegetable. Fresh leaves also have some flavouring use, for example in Western Javanese cooking, where they complement hot sambal.
	Since the pungency of paracress is wholly distinct to that of both black pepper and chillies it is an interesting alternative that should be tried by innovative cooks. It performs well as a substitute for pepper in European foods, to which it lends an unconventional, tickling yet subtle pungency.