$$ — 40% ABV — Orange
What people often imagine when they think of 'orange flavor' is likely the product of many varieties of citrus, including the lahara, a bitter orange that made famous the Caribbean island of Curaçao [kur-uh-saoh]. It would be quite hilarious to watch someone try to eat a raw lahara, but making the orangiest of orange flavors without it is rather difficult.
Dutch settlers in Curaçao tried growing their own Seville oranges, the preferred fruit for marmalade, but the climate resulted in a fruit with very little juice and a thick and oily rind. The colonists were first at a loss for what to do with their labors, but eventually the fruit would play as the backbone for a staple liqueur in the cocktail world: triple sec.
Sophisticated, clean, sweet, sour and mildly bitter, Cointreau is one of the world's very best triple secs and a genius ingredient for French toast. It's clear and fragrant, lacking the artificial neon colorings, cloying sweetness and flat flavors that plague many triple sec brands.
There's only a few items a cocktail bar seriously can't do without, and this is one of them. More even than their base spirit, cocktails like the Margarita or the Cosmopolitan hinge on their liqueur and there's a reason 99% of bars have a bottle of Cointreau on hand: it's just that good.