In the bottom of a cocktail shaker, gently muddle 6 mint leaves, 1 tsp Simple Syrup, and half of a peach. (The peach half should be pitted and diced).
To the shaker, add 2 ounces of Bourbon, ¾ ounce of Cointreau, and ice.
Shake until chilled and strain into a Rocks glass filled with lots of fresh ice.
Garnish with a sprig of fresh mint.