How to Make It
In a chilled julep cup, muddle the mint leaves. Add the tequila, sherry, Cocchi Americano, Simple Syrup and both bitters; fill with crushed ice and mix by spinning a swizzle stick or bar spoon between your hands. Top with more crushed ice and garnish with the blackberry. Lightly crush the mint sprig with your fingers to release the oils, then add it to the cup as garnish. Serve with a metal spoon-straw.