Cointreau is a well-known liqueur from western France, where it was first made more than a century and a half ago in the city of Angers. Colorless and with a strong, pleasing aroma, it has an exotic flavor that is a marriage of sweet orange peels from Spain and bitter orange peels from the Caribbean island of Curacao. Although similar to triple sec, Cointreau is drier. You will find it sold in a distinctive square bottle with a bright red ribbon. A popular after-dinner liqueur, Cointreau is also often used as a flavoring ingredient, as in this tart recipe.