In the bottom of a cocktail shaker, gently muddle 4 blackberries and 1½ ounces of Bourbon.
To the cocktail shaker, add ice, ¾ ounce of lemon juice, ½ ounce of Crème de Mûre, and 5 leaves of basil.
Shake until chilled.
Strain into a Rocks glass filled with fresh ice.
Garnish with a fresh blackberry and leaf of basil.