A Moulin Rouge cocktail is a drink made of just four simple ingredients, all of which are common bar ingredients. While the formula of apricot brandy, gin and lemon juice was used before this cocktail was invented, no one added grenadine syrup (at least in publication) until Harry Craddock's "The Savoy Cocktail Book," in 1930. The following recipe is almost exactly like the original, though it has been altered just a bit for more modern tastes.
Fill a cocktail shaker halfway with crushed ice.
Add the apricot brandy, gin, lemon juice and grenadine syrup to the cocktail shaker. Cover the cocktail shaker and shake gently for 15 to 20 seconds. Don't shake too hard, you'll bruise the gin.
Strain the contents of the cocktail shaker into a chilled cocktail glass. Garnish the drink with a maraschino cherry and serve right away.