I found this recipe on liquor.com.

gin, St-Germain, grapefruit juice⁣
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No history to share here, because this drink (like my last post) is another new drink that tastes like a 1920s drink. St-Germain liqueur has only been around since 2007.⁣
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No doubt – gin and St-Germain make beautiful music together. This drink is another favorite. ⁣