From the Food & Wine Cocktail book. This take on a margarita is dangerously delicious.

Ingredients:

8 blackberries (2 skewered on a pick)
10 mint leaves
1 ½ oz reposado tequila
1 oz fresh lime juice
1 oz simple syrup

In a cocktail shaker, muddle 6 of the berries.
Add ice, the mint, tequila, lime juice,and simple syrup; shake well.
Pour into a rocks glass; top with 2 berries.