In the bottom of a cocktail shaker, gently muddle 3 slices of cucumber together with 6 fresh mint leaves.
Add in 2 ounces of Bourbon, 1 ounce of lime juice, and 1 ounce of simple syrup.
Fill with ice and shake until well chilled.
Finely strain the mixture into a Rocks glass filled with ice. This will remove any bits of mints or cucumber seeds.
Garnish with a slice of cucumber and/or sprig of mint.