Before you begin mixing your drink, start by preparing the glass in which you will be serving the cocktail. Place a martini glass in the refrigerator, so that it is cool and misted with frost by the time you are ready to pour in the drink and serve it. Do not place the glass in the freezer, particularly if it is delicate, as this could cause it to crack and shatter.
Now, while the glass is chilling in the refrigerator, you can begin mixing your drink. Start by taking a large cocktail mixing glass, and fill a little more than a quarter of this with ice cubes, or crushed ice – the latter will cool your drink faster but give it a slightly watery taste, so choose whichever type of ice you prefer.
Once the ice is in the cocktail mixing glass, proceed to pour in the gin, dry vermouth, and the sweet vermouth. Use a drink stirring rod to mix the liquors in the glass – swirl them together for about 4 to 5 seconds, in order to mix them properly.
Now that the drink is ready, take the martini glass out of the refrigerator, and use a metal strainer to strain the drink into it. Top the cocktail with 2 dashes of Angostura bitters, and garnish with a fresh olive. Your Nineteenth Hole cocktail is now ready to serve.