Rusty Nail Cocktail Recipe - Liquor.com Nov 25, 2020 · As with lots of classics, the recipe varies widely. Ted Haigh, the author of “Vintage Spirits and Forgotten Cocktails,” likes two parts scotch to one part Drambuie; “Old Mister Boston” calls for a one-to-one ratio; and many modern versions are far drier, with some suggesting four parts whisky to one part liqueur. You could also substitute bourbon for scotch and get a Rusty Spike.