Muddle the two blackberries in a shaker and then add a handful of ice to the container.

Add the vodka, lemon juice and St. Germain to the shaker and shake for 10-15 seconds to thoroughly chill the contents.

Fill a cocktail glass with ice and using a strainer, pour the contents of the shaker into the glass.

Garnish with an additional blackberry on a decorative toothpick.