
Orange curaçao is a sweetened liqueur flavored with dried orange peel. It is named after the Caribbean island of Curaçao, where the bitter laraha orange grows.
Grand Marnier
Closest in weight and goes in at the same amount.
Also works, with a drier, plainer orange note.
No stand-in: it has far less sugar and no alcohol, so the drink turns thin and sour.
Blue and green curaçao are the same liqueur with coloring added, so the choice is about looks, not flavor.
Martinez
Genever