History of the Sidecar:
Two Parisian bars lay claim to the invention of the Sidecar--Harry's New York Bar, and the venerable Bar Hemmingway at the Ritz Hotel--but most agree it was inspired by the request of a WWI American Army Captain stationed in the city, who arrived on his motorcycle (replete with sidecar) and asked the bartender for a cocktail that would help take off the chill.
The bartender was caught in a dilemma: a drink to remove a chill would appropriately be brandy, but brandy was traditionally an after-dinner drink, and his patron wanted something prior to dinner. In the end, the bartender combined cognac, Cointreau, and lemon juice to mix a cocktail that highlighted the warming qualities of both the brandy and the Cointreau while boasting enough tartness to qualify as an anytime, any-season cocktail.
In the 1920s, the Sidecar became a signature drink of the Hemingway/Miller ex-patriot crowd in post-war Paris. Introduced to London not long after by Pat MacGarry of the Buck's Club, the drink--defined as equal parts Cognac, Cointreau, and lemon juice by "the French school"--experienced an English revision that left it listed as two Cognac and one each Cointreau and lemon juice by the 1930 Savoy Cocktail Book. Popular through the end of WWII, it was mysteriously forgotten for decades; The New York Times was the first outlet to report a Sidecar renaissance happening in swank NYC bars last year, and the Ritz currently sells a 400-euro Sidecar that holds the Guinness world record for more expensive cocktail.
Ingredients are mixed with ice in a cocktail shaker and strained into a chilled cocktail glass. The drink, which should have a noticeably velvet-like finish, is garnished with lemon or orange and can be served with a sugared rim.