Muddle one blackberry in a cocktail shaker. Add remaining ingredients (except for creme de mure and raspberries) into the shaker followed by ice. Shake quickly and strain into a rocks glass. In another shaker, muddle raspberries and creme de mure into a very fine paste. Breifly agitate the mixture and then top the glass with crushed ice. Float berry paste evenly on top of the ice. Garnish with a raspberry and a short straw.