According to cocktail historian David Wondrich, mint juleps were originally made with cognac. Bourbon was probably adopted as a substitute by Southerners after the Civil War.
The julep is the ultimate sultry-weather cooler.
Yield: makes 1 Cocktail
2 tbsp. superfine sugar
10 spearmint leaves, plus extra for garnish
1-2 tbsp. simple syrup
1⁄2 cup Kentucky bourbon
Put sugar on a plate. Moisten the rim of a glass (if you have a silver julep cup, that's even better) with a damp towel. Press rim of glass into some of the sugar to coat.
Put leaves and simple syrup into glass. Crush leaves very gently with a pestle, just enough to bruise them. Fill to the brim with crushed ice, then pour in bourbon to cover ice. Stir one turn with a swizzle stick. Garnish with a leafy sprig of spearmint.