The Rusty Nail cocktail is best prepared in a cocktail shaker, but if you do not have one readily available, you can also use an electric blender. The only factor that needs to be kept in mind when using an electric blender is that the drink should be blended on low speed, and for a maximum of 8 seconds.
Begin by adding a small amount of crushed ice to the cocktail shaker/electric blender – it is best to fill around a quarter of it with crushed ice. Then, start pouring in the ingredients for the drink, one at a time. Add the 1 1/2 oz of scotch to the cocktail shaker/electric blender, and follow it up by pouring in 3/4 oz of Drambuie.
Now, grasp the cocktail shaker firmly, and shake it vigorously for around15 seconds, until all the ingredients are thoroughly blended, and the ice has had sufficient time to cool the contents of the cocktail shaker. If you are using an electric blender instead, simply pulse it for around 8 seconds on low speed, to ensure that all the ingredients are mixed together.
Then, take two cocktail glasses (bucket glasses are classic, and fitting for a drink of this sort), hold a strainer over them, and pour in the drink, leaving around an inch and a half of space at the top of the glass. Finally, garnish the drinks with twists of lemon zest, and serve chilled.