David Wondrich: "New York's Colony was no ordinary speakeasy. It was where Vanderbilts and Windsors went to dine in a civilized manner, and if that included a drink or two, then bartender Marco Hattem would provide one, no questions asked.
Shake well with cracked ice:
1 1/2 oz gin
3/4 oz grapefruit juice
2 tsp maraschino
Strain into chilled cocktail glass."
(Article is at "Celebrate Prohibition Repeal," here.)