What is Blancmange or a Blancmange?
#1. 
Blancmange, pronounced , is a jelly dessert made of milk and/or cream, sugar, gelatin or cornstarch, and flavouring (usually almond). It is set in a mould and served cold. The term blancmanger also exists derived from the same source (although it is generally considered archaic or obsolete). The latter term generally refers to the older (medieval) recipes whereas blancmange is generally used to refer to the modern varieties.
Blancmange originated in the Arab world where it is known as "mehallabiyyah" (gets eaten quickly, presumably because it is good) and reached medieval Europe through Sicily and Spain. Its basic form involved shredded capon flesh (cf. tavuk gögsü ), and almond milk or ground almonds, often with rosewater, boiled together into a thick soup or runny stew. In the 16th century, a meatless version using cream, sugar and eggs was developed, and towards the end of the 17th century, a new kind of blancmange, a calf's foot or hartshorn jelly flavoured with almond and rosewater, and perhaps including milk, was introduced. In the 19th century, this was prepared using arrowroot, today cornflour is usually used. Blancmanges are usually pink or white.
The term blancmange is derived from the Middle English blankmanger, from Old French blanc mangier: blanc, white (of Germanic origin) + mangier, to eat, food (from Latin manducare). Several medieval recipes for blancmange have survived, and the dish is mentioned in the prologue to Geoffrey Chaucer's Canterbury Tales.
#2. 
Blancmange were a synthpop band in the 1980s.
They were formed in Harrow, London in 1979, by vocalist, Neil Arthur (born on 15 August 1958, in Darwen, Lancashire); and instrumentalist Stephen Luscombe (born on 29 October 1954, in Hillingdon, Middlesex). They released their first EP "Irene and Mavis" the following year, but had their first real exposure via a track on the seminal Some Bizarre compilation album, alongside fellow acts Soft Cell and Depeche Mode. This led to them signing a deal with London Records.
Their first success was the Talking Heads influenced single "Feel Me", a minor hit in 1982, but later that year they broke through with the single "Living on the Ceiling" (below), which made Number 7 in the UK singles chart. Arguably their seminal moment arrived in 1984, when they elected to cover ABBA's single "The Day Before You Came" - a brave move, as ABBA were then unfashionable. The single reached No 22 in the UK. According to an article by Stephen Thanabalan on the New Wave Revival in Rolling Stone, they were one of the New Romantic's biggest propagating machines for the movement emanating out of London and Essex. Eventually as synthpop became less fashionable, the band's fortunes declined, with the 1985 single "What's Your Problem" only reaching No. 40, and the same year's album Believe You Me spending only two weeks in the British album chart. Blancmange split up in 1986.
Luscombe later released an album of Indian influenced music, New Demons, with Pandit Dinesh, under the name 'The West India Company', in 1989. Arthur meanwhile released his solo album Suitcase, in 1994.
As stated on the band's official MySpace page, Blancmange have recently reformed and are writing material for a new album.