Place the mint leaves, sugar and water in an 8 ounce silver julep cup or highball glass. With a bar spoon, crush the mint, and then stir until the sugar dissolves. Pour in the bourbon and pack the glass tightly, almost to the top, with crushed ice. With a long-handled bar spoon, jiggle the mixture to mix the ice and bourbon together (do not stir) until the outside of the container is heavily frosted. Place several sprigs of fresh mint on the top before serving.
Makes 1 drink.