BUILD: Add ½ cup ice to a rocks glass. Pour in 1 ½ ounces gin and 5 ounces grapefruit juice.
STIR: Stir with a bar spoon for about 10 seconds, until well chilled.
GARNISH: Add 1 lime slice and serve immediately.
Notes
Make-Ahead: This cocktail is best made fresh. You can pre-chill the gin and grapefruit juice to speed things up.Ingredient Note: Fresh-squeezed grapefruit juice gives the brightest flavor, but high-quality refrigerated juice works well too.Variation: For a Salty Dog, run a lime wedge around the rim of the glass and dip it in kosher salt before adding ice.Glassware Tip: A rocks glass keeps the drink cold without over-diluting.